WO2018169112A1 - Electrolyte additive for lithium secondary battery and method for preparing same, electrolyte comprising additive and method for preparing same, and lithium secondary battery comprising additive - Google Patents

Abstract

Provided are a functional additive comprising a reduction-degradable additive, an oxidation-degradable additive, and a reactive additive and a method for preparing same, an electrolyte comprising the functional additive and a method for preparing same, and a lithium secondary battery having the functional additive applied thereto.

Description

 【Specification】

 [Name of invention]

 Electrolyte Additive for Lithium Secondary Battery and Manufacturing Method Thereof, Electrolyte Containing the Additive and Manufacturing Method Thereof, and Lithium Secondary Battery Lithium Secondary Battery

 Technical Field

 The present invention relates to an electrolyte additive for a lithium secondary battery, a method for manufacturing the same, an electrolyte including the additive, a method for producing the same, and a lithium secondary battery including the additive.

 [Technique to become background of invention]

 Recently, interest in medium-capacity lithium secondary batteries for application to next-generation automotive power supplies has been increasing.

 In this regard, when a lithium-containing layered oxide containing an excessive amount of lithium (ie, a lithium-rich) layered oxide is used as the positive electrode active material, the layer charge driving voltage of the battery may be improved, and a silicon-based material as well as a carbon-based material may be used. Since it can be used as a negative electrode active material, the capacity of a battery can be improved.

 Meanwhile, in a typical lithium secondary battery, lithium salt dissolved in an organic solvent is used as an electrolyte. The overlithium positive electrode active material generates a high-voltage environment and generates oxygen gas during the first layer charge, and the silicon-based negative electrode active material is repeatedly charged and discharged. As a result, severe volume expansion occurs and cracking is formed on the surface of the electrode, which eventually causes decomposition reaction of the electrolyte on the surface of the electrode to which each active material is applied.

 As a result, the electrolyte is gradually depleted and the electrochemical performance of the battery is rapidly deteriorated. As a result, a thick film acting as a resistance is formed on the surface of each electrode, so that the rate of electrochemical reaction of the battery is reduced, and the decomposition of the electrolyte is generated. There is a problem that the acidic material (for example, HF, etc.) to melt each electrode film or damage the positive electrode active material to ensure the electrochemical stability of the battery.

 [Content of invention]

Problem to be solved In order to solve the above-mentioned problems, the present invention provides materials (ie, additives) added to an electrolyte for a lithium secondary battery, a method of manufacturing the same, and a lithium secondary battery comprising the same.

 Specifically, in one embodiment of the present invention, a material capable of being oxidatively decomposed to form a protective film on the surface of the anode is provided as an oxidative decomposition type additive.

 In another embodiment of the present invention, together with the oxidative decomposition type additive, a reduction decomposition type additive, which is a substance that is reduced and decomposed to form a protective film on the surface of the negative electrode, and an additive having a semi-ungung additive capable of removing an acidic substance to provide. In addition, as another embodiment of the present invention, there is also provided a method for preparing an additive according to each of the above embodiments, an electrolyte including the additive, a method for preparing the same, and a lithium secondary battery to which the additive is applied.

 [Measures of problem]

 In one embodiment of the present invention, an electrolyte additive for a lithium secondary battery, which is an oxidative decomposition type additive, including a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a mixture thereof:

[Formula 1]

n

상기 화학식 1 및 2에서, 및 ¾는 각각， 서로 독립적으로, 수소， 치환 또는 비치환된 C1 내지 C8 알콕시기, 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. 또한, ¾ 및 1 ₂는 각각, 서로 독립적으로, 수소， 치환 또는 비치환된 C1 내지 C8 알킬기, 치환 또는 비치환된 C1 내지 C8 퍼플루오로 알킬기, 치환 또는 비치환된 C6 내지 C30 아렌 (arene)기， 치환 또는 비치환된 C6 내지 C30 퍼플루오로 아렌 (arene)기, CF₃, 할로겐 원소 (F, CI, Br, or l), 또는 이들의 조합이다. 그리고 , η은 1 또는 2 이고， m은 1 또는 2 이다. 구체적으로， 상기 산화 분해형 첨가제는, 리튬 다이플루오로 (말로네이토) 보레이트 (Lithium difluoro(malonato)borate, JB-HLiB), 리튬 다이플루오로 (플루오로말로네이토) 보레이트 (Lithium difluoro(fluoroinalonato)borate, JB-FLiB), 리튬 다이플루오로 (다이플루오로말로네이토) 보레이트 (Lithium difluoro(difluoromalonato)borate, JB-DFLiB), 리튬 다이플루오로 (브로모말로나토)보레이트 (lithium difluoro(bromomalonato)borate), 리튬 다이플루오로 (클로로말로나토)보레이트 (lithium difluoro(c loromalonato)borate), 리튬 다이플루오로 (아이오도말로나토)보레이트 (lithium difluoro(iodomalonato)borate), 리晉 다이플루오로 (페닐말로나토)보레이트 (lithium difluoro(phenylmalonato)borate), 리튬 다이플루오로 (퍼플루오로말로나토)보레이트 (lithium difluoro(perfluoromalonato)borate), 리튬 다이플루오로 (트라이플루오로메틸말로나토)보레이트 (lithium difluoro(trifluoromethylmalonato)borate), 리튬 비스 (말로나토)보레이트 (lithium bis(malonato)borate), 리튬 비스 (플루오로말로나토)보레이트 (lithium bis(fluoromalonato)borate), 리튬 비스 (다이플루오로말로나토)보레이트 (lithium bis(difluoromalonato)borate), 리튬 비스 (페닐말로나토)보레이트 (lithium bis(phenylmalonato)borate), 리륨 비스 (퍼플루오로말로나토)보레이트 (lithium bis(perfluoromalonato)borate), 리튬 비스 (트라이플루오로메틸말로나토)보레이트 (lithium bis(trifluoromethylmalonato)borate) 중에서 선택되는 적어도 하나 이상일 수 있다. [Formula 2]

In Formulas 1 and 2, and ¾, respectively, independently of each other, hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof. In addition, ¾ and 1 ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene (arene) Groups, substituted or unsubstituted C6 to C30 perfluoro arene (arene) groups, CF ₃ , halogen elements (F, CI, Br, or l), or a combination thereof. And η is 1 or 2, and m is 1 or 2. Specifically, the oxidative decomposition type additive, lithium difluoro (malonate) borate (Lithium difluoro (malonato) borate, JB-HLiB), lithium difluoro (fluoromalonate) borate (Lithium difluoro (fluoroinalonato) borate, JB-FLiB), lithium difluoro (difluoromalonato) borate (Lithium difluoro (difluoromalonato) borate, JB-DFLiB), lithium difluoro (bromomalonato) borate (lithium difluoro (bromomalonato) borate), lithium difluoro (c loromalonato) borate, lithium difluoro (iodomalonato) borate, lithium difluoro (both) Lithium difluoro (phenylmalonato) borate, lithium difluoro (perfluoromalonato) borate, lithium difluoro (trifluoromethylmalona) Borate (lithium difluoro (trifluoromethylmalonato) borate), lithium bis (malonato) borate), lithium bis (fluoromalonato) borate (lithium bis (fluoromalonato) borate), lithium bis (difluoro Lithium bis (difluoromalonato) borate, lithium bis (phenylmalonato) borate, lithium bis (perfluoromalonato) borate, lithium bis (difluoromalonato) borate It may be at least one selected from lithium bis (trifluoromethylmalonato) borate.

In another embodiment of the present invention, the compound represented by the following formula (3) And reacting the boron raw material to produce an oxidatively decomposable additive, which provides a method for producing an electrolyte additive for a lithium secondary battery.

상기 화학식 3에서, Ri 및 1 ₂는 각각, 서로 독립적으로, 수소， 치환 또는 비치환된 C1 내지 C8 알킬기, 치환 또는 비치환된 C1 내지 C8 퍼플루오로 알킬기, 치환 또는 비치환된 C6 내지 C30 아렌 (arene)기, 치환 또는 비치환된 C6 내지 C30 퍼플루오로 아렌 (arene)기, CF₃, 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. 또한， A는 리륨, 소듐, 또는 수소이다. 구체적으로, 상기 붕소 원료 물질은, 하기 화학식 4로 표시되는 화합물, 리튬 테트라플루오로보레이트 (Lithium tetrafluoroborate, LiBF₄), 또는 이들의 조합일 수 있다.

In Formula 3, Ri and 1 ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene (arene) group, substituted or unsubstituted C6 to C30 perfluoro arene (arene) group, CF ₃ , halogen element (F, CI, Br, or I), or a combination thereof. In addition, A is lithium, sodium, or hydrogen. Specifically, the boron raw material may be a compound represented by Chemical Formula 4, lithium tetrafluoroborate (LiBF ₄ ), or a combination thereof.

상기 화학식 4에서, R₃ 및 R4는 각각, 서로 독립적으로, 수소, 치환 또는 비치환된 C1 내지 C8 알킬기, 치환 또는 비치환된 C1 내지 C8 퍼플루오로 알킬기, 치환 또는 비치환된 C6 내지 C30 아렌 (arene)기, 치환 또는 비치환된 C6 내지 C30 퍼플루오로 아렌 (arene)기, CF₃, 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. 또한, X는 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. [Formula 4]

In Formula 4, R ₃ and R 4 are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene (arene) group, substituted or unsubstituted C6 to C30 perfluoro arene (arene) group, CF ₃ , halogen element (F, CI, Br, or I), or a combination thereof. In addition, X is a halogen element (F, CI, Br, or I), or a combination thereof.

In addition, the step of preparing the oxidative decomposition type additive; at a temperature range of 0 to 150 ^° C, carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, aprotic solvent, or a combination thereof Using solvent, wet It may be carried out, the execution time may be greater than 0 hours and up to 24 hours ᅳ step of preparing the oxidative decomposition type additive; in the compound represented by the following formula (1), the compound represented by the following formula (2), or their The mixture can be prepared.

[Formula 1]

상기 화학식 1 및 2의 구체적인 사항은 전술한 바와 같아 생략한다. 본 발명의 다른 일 구현예에서는， 플루오로에틸렌 카보네이트 (fluoroethylene carbonate, FEC) 및 비닐렌 카보네이트 (vinylene carbonate, VC) 중 하나， 또는 이들의 흔합물을 포함하는, 환원 분해형 첨가제 ; 하기 화학식 1로 표시되는 화합물, 하기 화학식 2로 표시되는 화합물， 또는 이들의 흔합물을 포함하는, 산화 분해형 첨가제; 및 실릴 (silyl)기를 포함하는 화합물인 반응형 첨가제를 포함하는, 첨가제；를 포함하는, 리튬 이차 전지용 전해질 첨가제를 제공한다: [화학식 1] [Formula 2]

Specific details of Chemical Formulas 1 and 2 are omitted as described above. In another embodiment of the present invention, a reduction decomposition type additive, including one of fluoroethylene carbonate (FEC) and vinylene carbonate (VC), or a combination thereof; An oxidative decomposition type additive comprising a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a mixture thereof; And an additive, comprising a reactive additive which is a compound containing a silyl group. [Formula 1]

상기 화학식 1 및 2의 구체적인 사항은 전술한 바와 같아 생략한다. 한편, 상기 환원 분해형 첨가제: 산화 분해형 첨가제의 중량비는, 5:2 내지 12:0.05이고, 환원 분해형 첨가제: 반웅형 첨가제의 중량비는， 5:5 내지 12:0.1일 수 있다. [Formula 2]

Specific details of Chemical Formulas 1 and 2 are omitted as described above. On the other hand, the weight ratio of the reduction decomposition type additive: oxidative decomposition type additive is 5: 2 to 12: 0.05, the weight ratio of the reduction decomposition type additive: semi-finished additive may be 5: 5 to 12: 0.1.

 The oxidatively decomposable additive may be at least one selected from the above materials.

The reactive additive is. Tris (trimethylsilyl) phosphite (TMSP), Tris (trimethylsilyl) methane (T-TMSM) Bis (trimethylsilyl) methane (B- BMSM), Tris (trimethylsilyl) amine (T-TMSA), Bis (trimethylsilyl) amine (B is (trimethylsilyl) amine, B-TMSA), Bis (trimethylsilyl) sulfide bis (trimethylsilyl Sulfide Bis (trimethylsilyl) sulfide, B-TMSSi), Bis (trimetylsiloxy) et ane, B-TMSE), Bis (trimethylsilylt io) ethane, B -TMSSE), Trimethylsilyl isothiocyanate (TMS ITC), Trimethylsilyl isocyanate (TMS IC), trimethyl (phenylselenometliyl) silane (TMPSeS), trimethyl ( Phenylthiomethyl) silane Trimethyl (phenyltliiometliyl) silane, TMPSS), and N, O-bis (trimethylsilyl) acetamide (N, 0-Bis (trimethylsilyl) acetamide, B-TMS AI), bis (trimethylethylsilyl) It may be at least one selected from sulfur diamide (Bis (trimethylsilyl) sulfor dilimide, B-TMS SDI).

 In another embodiment of the present invention, by reacting the compound represented by the formula (3) and the boron raw material to prepare an oxidative decomposition type additive; And mixing the oxidatively decomposable additive with the reductively decomposable additive and the reactive additive, wherein the reductive decomposition additive includes fluoroethylene carbonate (FEC) and vinylene carbonate (vinylene carbonate, VC). ), Or a combination thereof, wherein the semi-formular additive is a compound comprising a silyl group, providing a method for preparing an electrolyte additive for a lithium secondary battery:

상기 붕소 원료 물질은, 하기 화학식 4로 표시되는 화합물， 리튬 테트라플루오로보레이트 (Lithium tetrafluoroborate, LiBF₄), 또는 이들의 조합일 수 있다.

The boron raw material may be a compound represented by the following Chemical Formula 4, lithium tetrafluoroborate (Lithium tetrafluoroborate, LiBF ₄ ), or a combination thereof.

상기 화학식 3 및 4의 구체적인 사항과, 상기 산화 분해형 첨가제를 제조하는 단계;의 구체적인 사항은, 전술한 바와 같아 상세한 설명을 생략한다. [Formula 4]

Specific details of Chemical Formulas 3 and 4, and the oxidative decomposition type additive Specific steps of the manufacturing step; as described above, detailed description thereof will be omitted.

 In another embodiment of the present invention, an organic solvent; First lithium salt; And an additive; wherein the additive is an oxidative decomposition type additive including a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a combination thereof, and provides an electrolyte for a lithium secondary battery.

[Formula 1]

상기 화학식 1 및 2에 대한 구체적인 사항은 전술한 바와 같아, 상세한 설명을 생략한다. [Formula 2]

Specific details of Chemical Formulas 1 and 2 are as described above, and detailed description thereof will be omitted.

 The content of the oxidative decomposition type additive in the electrolyte may be 0Ό5 to 2% by weight.

The first lithium salt is, lithium hexafluorophosphate (Lithium hexafluorophosphate, LiPF ₆ ), lithium tetrafluoroborate (Lithium tetrafluoroborate, LiBF ₄ ), lithium perchlorate (Lithium perchlorate, LiC10 ₄ ), lithium nuxafluoroarsenate (Lithium hexafluoro arsenate, LiAsF ₆ ), lithium Lithium bis (oxalato) borate (LiBOB), Lithium bis (fluorosulfonyl) imide (LiFSI) and Lithium fluoro (oxalate) borate (LiFOB) It may be at least one selected from among.

 The concentration of the first lithium salt in the electrolyte may be 0.1 to 2 M.

 The organic solvent is a carbonate, ester ,. It may be an organic solvent which is an ether type, a ketone type, an alcohol type, an aprotic solvent, or a combination thereof. For example, it may be ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (dimethyl catbonate, DMC), diethyl carbonate (DEC), or a combination thereof. .

 In another embodiment of the present invention, by reacting the compound represented by the formula (3) and the boron raw material to prepare an oxidative decomposition type additive; And mixing the oxidative decomposition type additive with a crab 1 lithium salt and an organic solvent to obtain an electrolyte.

상기 화학식 ₃, 상기 산화 분해형 첨가제를 제조하는 단계;， 및 상기 산화 분해형 첨가제와, 제 1 리튬염, 및 유기 용매를 흔합하여 수득된 첨가제에 대한 구체적인 사항은 전술한 바와 같아， 상세한 설명을 생략한다. 본 발명의 다른 일 구현예에서는, 유기 용매; 게 1 리튬염; 및 환원 분해형 첨가제, 산화 분해형 첨가제, 및 반웅형 첨가제를 포함하는， 첨가제；를 포함하되, 상기 환원 분해형 첨가제는 플루오로에틸렌 카보네이트 (fluoroethylene carbonate, FEC) 및 비닐렌 카보네이트 (vinylene carbonate, VC) 중 하나, 또는 이들의 흔합물을 포함하고, 상기 산화 분해형 첨가제는 하기 화학식 1로 표시되는 화합물, 하기 화학식 2로 표시되는 화합물, 또는 이들의 흔합물을 포함하고, 상기 반웅형 첨가제는 실릴 (silyl)기를 포함하는 화합물인, 리튬 이차 전지용 전해질을 제공한다. [Formula 3]

Formula _3, wherein the oxidation step for producing a decomposable additive; details of the, and the additive obtained common combined with the oxidizing decomposable additives, the first lithium salt, and an organic solvent is like described above, the detailed description Omit. In another embodiment of the present invention, an organic solvent; Crab 1 lithium salt; And an additive, including a reduction decomposition additive, an oxidative decomposition additive, and a semi-ung additive, wherein the reduction decomposition additive includes fluoroethylene carbonate (FEC) and vinylene carbonate (VC). ), Or a combination thereof, and the oxidatively decomposable additive is a compound represented by the following Chemical Formula 1, A compound, or a mixture thereof, and the semi-amorphous additive provides a electrolyte for a lithium secondary battery, which is a compound containing a silyl group.

[Formula 1]

상기 화학식 1 및 2의 구체적인 사항은 전술한 바와 같아, 상세한 설명을 생략한다. [Formula 2]

Specific details of Chemical Formulas 1 and 2 are as described above, and a detailed description thereof will be omitted.

 The amount of the additive in the electrolyte may be 5 to 19% by weight of the total weight of the electrolyte 100% by weight.

The total weight of the additive increases by 100% by weight, the reduction decomposition type additive is included 5 to 12% by weight ⁰ /., The oxidative decomposition type additive is contained 0.05 to 2% by weight, the semi-finished additive is 0.1 to 5% by weight It may be included.

 The said system 1 lithium salt,

 The concentration of the first lithium salt in the electrolyte, and the details of the organic solvent are as described above, and a detailed description thereof will be omitted.

In another embodiment of the present invention, represented by the following formula (3) Reacting the compound and the boron raw material to produce an oxidative decomposition type additive; And mixing the oxidative decomposition type additive with a reduction decomposition type additive, a semi-amorphous additive, a first lithium salt, and an organic solvent to obtain an electrolyte, wherein the reduction decomposition additive includes fluoroethylene carbonate ( fluoroethylene carbonate (FEC) and one of the vinylene carbonate (vinylene carbonate, VC), or a mixture thereof, the semi-finished additive is a compound containing a silyl group, a method for producing an electrolyte for a lithium secondary battery to provide:

상기 화학식 3에 대한 구체적인 사항은 전술한 바와 같아， 상세한 설명을 생략한다. [Formula 3]

Details of the formula (3) are as described above, detailed description thereof will be omitted.

 In another embodiment of the present invention, a positive electrode including a lithium-rich positive electrode active material; A negative electrode including a silicon-based negative active material; And an electrolyte comprising an organic solvent, a first lithium salt, and an additive; wherein the additive is an oxidative decomposition type including a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a combination thereof It provides a lithium secondary battery which is an additive.

In another embodiment of the present invention, a positive electrode including a lithium-rich positive electrode active material; A negative electrode including a silicon-based negative active material; And an electrolyte comprising an organic solvent, a system 1 lithium salt, and an additive, wherein the additive includes a reduction decomposition additive, an oxidative decomposition additive, and a semi-ung additive, wherein the reduction decomposition additive is fluoro. Ethylene carbonate (FEC) and one of vinylene carbonate (vinylene carbonate, VC), or a combination thereof, wherein the oxidative decomposition additive is a compound represented by the following formula (1), Compound, or a combination thereof, wherein the semi-formular additive is a compound comprising a silyl group, lithium Provide a secondary battery:

[Formula 1]

상기 화학식 1 및 2에 대한 구체적인 사항은 전술한 바와 같아, 상세한 설명을 생략한다. [Formula 2]

Specific details of Chemical Formulas 1 and 2 are as described above, and detailed description thereof will be omitted.

 In each of the lithium secondary batteries, a lithium-rich positive electrode active material may include a compound represented by the following Formula 5.

[Formula ⁵ ] Li _x Ni _y Mn _z Co _w 0 ₂

 In Formula 5, 1 <χ ≦ 2, 0 <y ≦ l, 0 <ζ ≦ 1, and 0 <w ≦ l. In each of the lithium secondary batteries, the silicon-based negative active material may be a combination of graphite and silicon, a material coated with silicon on the surface of the graphite particles, or a material simultaneously coated with silicon and carbon on the surface of the graphite particles.

 The average layer voltage of the gig-lithium secondary battery may be 4.5 V or more. 【Effects of the Invention】

According to one embodiment of the present invention, a high-voltage and high-capacity lithium battery is applied by simultaneously applying an overlithium cathode active material and a silicon-based anode active material. At the same time, the electrochemical performance, reaction speed and stability of the battery may be improved by the functional additive included with the organic solvent and the first lithium salt.

 Specifically, a protective film may be formed on the surface of the anode by an oxidative decomposition type additive.

 In addition, the protective film is formed on the surface of the positive electrode by the oxidative decomposition type additive, the protective film is formed on the surface of the negative electrode by the reduction decomposition type additive, it may be performed at the same time to remove the acidic material by the reactive additive.

 [Brief Description of Drawings]

 1 is an exploded perspective view of a rechargeable lithium battery according to one embodiment of the present invention.

 2 is a chemical structural diagram illustrating various oxidative decomposition type additives that may be included in a lithium secondary battery according to one embodiment of the present invention.

 FIG. 3 shows the results of evaluation of high temperature life characteristics of the overlithium positive electrode half cell of each lithium secondary battery of Example 1 and Comparative Example 1 of the present invention. 4 shows the evaluation results of room temperature life characteristics of the graphite negative electrode half cell of each lithium secondary battery of Example 2 and Comparative Example 2 of the present invention.

 FIG. 5 shows the results of evaluation of high rate discharge characteristics of the overlithium positive electrode half cell of each lithium secondary battery of Example 3 and Comparative Example 3 of the present invention. FIG. 6 shows the results of evaluation of room temperature life performance of a full cell using an overlithium positive electrode and a silicon-based negative electrode for each lithium secondary battery of Example 4 and Comparative Example 4 of the present invention.

 FIG. 7 shows changes in open circuit voltage during high temperature storage of a full cell using an overlithium positive electrode and a silicon-based negative electrode for each lithium secondary battery of Example 4 and Comparative Example 4 of the present invention.

 FIG. 8 shows capacity retention rates after high-temperature storage of a full cell using an overririum positive electrode and a silicon-based negative electrode for each of the lithium secondary batteries of Example 4 and Comparative Example 4 of the present invention.

9 is for each lithium secondary battery of Example 5 and Comparative Example 5 of the present invention The results of the evaluation of the room temperature life performance of a full cell using a LiCo0 ₂ anode and a graphite-based cathode are shown.

10 shows the results of evaluation of high temperature life performance of a full cell using a LiCo0 ₂ positive electrode and a graphite negative electrode for each lithium secondary battery of Example 5 and Comparative Example 5 of the present invention.

 Figure 11 shows the HF removal effect of the semi-ungsung additives of Example 6 and Comparative Example 6 of the present invention.

 [Specific contents to carry out invention]

 Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

 Lithium secondary batteries may be classified into lithium secondary batteries, lithium ion polymer batteries, and lithium polymer batteries according to the type of separator and electrolyte used, and may be classified into cylindrical, square, coin, and pouch types according to their type. Depending on the size, it can be divided into bulk type and thin film type. Since the structure and manufacturing method of these batteries are well known in the art, detailed description thereof will be omitted.

1 illustrates an example of a cylindrical lithium secondary battery 100, which includes a negative electrode 112, a positive electrode II ⁴ , a separator 113 disposed between the negative electrode 11 and a positive electrode II ⁴ , and the negative electrode 112. ), And an electrolyte (not shown) impregnated in the positive electrode 114 and the separator 113.

 In addition, the lithium secondary battery 100 may further include a battery container 120 and an encapsulation member 140 encapsulating the battery container 120. The lithium secondary battery 100 is configured by stacking the negative electrode 112, the separator 113, and the positive electrode 114 in order, and then storing the lithium secondary battery 100 in the battery container 120 in a state of being wound in a spiral shape.

The negative electrode 112 includes a current collector and a negative electrode active material layer formed on the current collector, and the negative electrode active material layer includes a negative electrode active material. The negative electrode active material may be a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, and may dope and undo lithium. Materials, or transition metal oxides are used.

 Among the negative electrode active materials, carbon-based materials such as graphite are widely known as materials capable of reversibly intercalating / deintercalating lithium ions, and graphite has a low discharge voltage of -0.2 V compared to lithium, and thus the negative electrode active material The battery having the high discharge voltage of 3.6 V provides the advantage in terms of the energy density of the lithium battery, and also the reversibility of ensuring the long life of the lithium secondary battery is the most widely used.

 However, the graphite active material has a problem of low capacity in terms of energy density per unit volume of the electrode plate due to the low graphite density (theoretical density of 2.2 gAx) in the production of the electrode plate, and it is easy to cause side reaction with the organic electrolyte used at high discharge voltage. There is a problem of occurrence of swelling and a decrease in capacity, and a silicon-based material having a high capacity as a material capable of doping and undoping lithium has been spotlighted as an alternative.

On the other hand, the positive electrode 114 includes a current collector and a positive electrode active material layer formed on the current collector. As the cathode active material, a compound (lithiated intercalation compound) capable of reversible intercalation and deintercalation of lithium may be used, and generally, LiCo0 ₂ , LiMn ₂ O ₄ , LiNii. _An oxide composed of lithium and a transition metal having a structure capable of intercalating lithium ions, such as _x Co _x O ₂ (0 <x <1), is mainly used.

 In recent years, a technique for improving the layer-electric driving voltage of a battery has been researched by using a lithium-rich layered oxide containing an excessive amount of lithium as a positive electrode active material. In this case, since the silicon-based material other than the carbon-based material can be used as the negative electrode active material, the capacity of the battery can be further improved.

Meanwhile, in a typical lithium secondary battery, a lithium salt dissolved in an organic solvent is used as an electrolyte. The overlithium positive electrode active material generates a high voltage environment and generates oxygen gas during the first layer discharge, and the silicon-based negative electrode active material repeatedly discharges the layer. As a result, severe volume expansion occurs and cracking is formed on the surface of the electrode, which eventually causes decomposition reaction of the electrolyte on the surface of the electrode to which each active material is applied. As a result, the electrolyte is gradually depleted and the electrochemical performance of the battery is rapidly deteriorated. As a result, a thick film acting as a resistance is formed on the surface of each electrode, so that the rate of electrochemical reaction of the battery is lowered, resulting in decomposition of the electrolyte. There is a problem that the acidic material (for example, HF, etc.) to melt each electrode film or damage the positive electrode active material to ensure the electrochemical stability of the battery.

 Electrolyte Additives for Lithium Secondary Batteries In connection with the above, embodiments of the present invention provide a combination of (1) an oxidatively degradable additive alone, and (2) a reductively degradable additive, an oxidatively degradable additive, and a semi-ung additive. A functional additive consisting of three additives is presented, respectively. The functional additive includes the reduction decomposition type additive, the oxidative decomposition type additive, and the semi-ung additive type, and in the following description, the three additives are collectively referred to as "additives" or black "functional additives". Shall be.

 m Oxidatively Degradable Additive Single Material The oxidatively decomposable additive is a material that functions to oxidatively decompose to form a protective film on the surface of the anode, and prevents electrolyte decomposition reaction from occurring at the surface of the anode.

 Therefore, when the oxidative decomposition type additive is added to the electrolyte, while implementing a lithium secondary battery of a high voltage by applying an over-lithium positive electrode active material, while maintaining the structure of the active materials while driving the battery, the electrochemical performance of the battery, It can contribute to improving reaction speed and stability. In this regard, in one embodiment of the present invention, to provide an electrolyte additive for a lithium secondary battery, which is an oxidative decomposition type additive, including a compound represented by the following formula (1), a compound represented by the following formula (2), or a mixture thereof do:

[화학식 2]

상기 화학식 1 및 2에서, 및 ¾는 각각, 서로 독립적으로, 수소， 치환 또는 비치환된 C1 내지 C8 알콕시기, 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. 또한, ¾ 및 R ₂는 각각, 서로 독립적으로, 수소, 치환 또는 비치환된 C1 내지 C8 알킬기, 치환 또는 비치환된 C1 내지 C8 퍼플루오로 알킬기, 치환 또는 비치환된 C6 내지 C30 아렌 (arene)기, 치환 또는 비치환된 C6 내지 C30 퍼플루오로 아렌 (arene)기, CF₃, 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. 아을러 , η은 1 또는 2 이고, m은 1 또는 2 이다. 예를 들어, 상기 산화 분해형 첨가제는, 리튬 다이플루오로 (말로네이토) 보레이트 (Lithium difluoro(malonato)borate, JB-HLiB), 리튬 다이플루오로 (플루오로말로네이토) 보레이트 (Lithium difluoro (fluoromalo nato)bor ate, JB-FLiB), 리튬 다이플루오로 (다이플루오로말로네이토) 보레이트 (Lithium difluoro (difluoromalonato)borate, JB-DFLiB), 리륨 다이플루오로 (브로모말로나토)보레이트 (lithium difluoro(bromomalonato)borate), 리튬 다이플루오로 (클로로말로나토)보레이트 (lithium difluoro(chloromalonato)borate), 리튬 다이플루오로 (아이오도말로나토)보레이트 (lithium difluoro(iodomalonato)borate), 리륨 다이플루오로 (페닐말로나토)보레이트 (lithium difluoro(p enylmalonato)borate), 리튬 다이플루오로 (퍼플루오로말로나토)보레이트 (lithium difluoro (perfluoromalo nato)borate), 리튬 다이플루오로 (트라이플루오로메틸말로나토)보레이트 (lithium difluoro (trifluoromethylmalo nato)bor ate) , 리륨 비스 (말로나토)보레이트 (lithium bis(malonato)borate), 리튬 비스 (플루오로말로나토)보레이트 (lithium bis(fluoromalonato)borate), 리륨 비스 (다이플루오로말로나토)보레이트 (lithium bis(difluoromalonato)borate), 리륨 비스 (페닐말로나토)보레이트 (lithium bis(phenylmalonato)borate), 리튬 비스 (퍼플루오로말로나토)보레이트 (lithium bis(perfluoromalonato)borate), 리튬 비스 (트라이플루오로메틸말로나토)보레이트 (lithium bis(trifluoromethylmalonato)borate) 중에서 선택되는 적어도 하나 이상일 수 있지만, 앞서 제시한 화학식 1로 표시되는 화합물, 화학식 2로 표시되는 화합물， 또는 이들의 흔합물을 포함하는 것이라면 특별히 제한되지 않는다. [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2, and ¾, respectively, independently of each other, hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof. In addition, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene (arene) Groups, substituted or unsubstituted C6 to C30 perfluoro arene groups, CF ₃ , halogen elements (F, CI, Br, or I), or combinations thereof. Alternatively, η is 1 or 2 and m is 1 or 2. For example, the oxidatively decomposable additive may include lithium difluoro (maloneto) borate (Lithium difluoro (malonato) borate (JB-HLiB), lithium difluoro (fluoromalonate) borate (Lithium difluoro ( fluoromalo nato) bor ate, JB-FLiB), lithium difluoro (difluoromalonato) borate (Lithium difluoro (difluoromalonato) borate, JB-DFLiB), lithium difluoro (bromomalonato) borate (lithium difluoro (bromomalonato) borate, lithium difluoro (chloromalonato) borate, lithium difluoro (iodomalonato) borate, lithium difluoro Lithium difluoro (p enylmalonato) borate, lithium difluoro (perfluoromalo nato) borate, lithium difluoro (trifluoromethylmalona) ) Borate (lithium difluoro (trifluoromethylmalo nato) bor ate), Lyrium bis (NATO words) borate (lithium bis (malonato) borate), lithium bis (fluoromalonato) borate, lithium bis (difluoromalonato) borate, lithium bis (phenylmalonato) ) Borate (lithium bis (phenylmalonato) borate), lithium bis (perfluoromalonato) borate, lithium bis (trifluoromethylmalonato) borate It may be at least one selected, but is not particularly limited as long as it includes a compound represented by Formula 1, a compound represented by Formula 2, or a combination thereof.

For more specific example, Figure 2 is the oxidative decomposition additive additive, lithium difluoro (malonato) borate (Lithium difluoro (malonato) borate, JB-HLiB), lithium difluoro (fluoromaloneto) Lithium difluoro (difluoromalonato) borate (JB-FLiB), Lithium difluoro (difluoromalonato) borate (JB-DFLiB), Lithium difluoro (bromomalonato) Borate (lithium difluoro (bromomalonato) borate), Lithium difluoro (chloromalonato) borate, Lithium difluoro (iodomalonato) borate, Lithium Lithium difluoro (phenylmalonato) borate, Lithium difluoro (perfluoromalonato) borate, Lithium difluoro (trimalmalonato) borate Lithium difluoro (trifluoromethylmalonato) borate, lithium bis (malonato) borate, lithium bis (fluoromalonato) borate, lithium bis (fluoromalonato) borate, Lithium bis (difluoromalonato) borate, Lithium bis (phenylmalonato) borate, Lithium bis (difluoromalonato) borate perfluoromalonato) borate) and lithium bis (trifluoromethylmalonato) borate). The oxidatively decomposable additive has a relatively low HOMO (High Occupied Molecular Orbital) energy than lithium salts used in electrolytes, and thus has a relatively high tendency to oxidatively decompose.

 Accordingly, the oxidative decomposition type additive may be oxidatively decomposed before the lithium salt in the electrolyte when the lithium secondary battery is driven, thereby forming a stable protective film on the surface of the positive electrode.

 In other words, the oxidative decomposition type additive may be oxidatively decomposed before the lithium salt in the electrolyte to form a solid electrolyte interface (SEI) on the surface of the positive electrode.

 Solid electrolyte interface (solid electrolyte interface, formed on the surface of the anode,

SEI) performs a function of stably protecting the positive electrode without acting as a resistance of the battery, thereby preventing the organic solvent, the primary lithium salt, from directly contacting the surface of the positive electrode.

 (2) functional additives consisting of three additives

 On the other hand, the functional additives are fluoroethylene carbonate (fluoroethylene carbonate, FEC) and vinylene carbonate (vinylene carbonate, VC) reduction decomposition type additive; Oxidative decomposition type additives having a higher tendency for oxidative decomposition than lithium salts in the electrolyte; And semi-additives which are compounds containing a silyl group; three kinds of additives.

1) The reduction decomposition additive is reduced decomposition to form a protective film on the surface of the cathode, 2) the oxidation decomposition additive is oxidatively decomposition _. A protective film is formed on the surface of the anode, and 3) the semi-finished additive performs a function of removing an acidic substance (for example, HF, etc.), and the functional additive includes all of the three additives, thereby providing a respective function. This is done at the same time.

 In other words, in the functional additive, the reduction decomposition type additive and the oxidative decomposition type additive mainly form a stable protective film on the surface of each electrode to prevent the aforementioned electrolyte decomposition reaction from occurring and at the same time, even if the electrolyte decomposition reaction occurs. The semi-aung form additive can effectively remove the acidic substance which is the decomposition product.

Accordingly, the functional additives, in particular, the per lithium positive electrode active material and By applying a silicon-based negative active material at the same time to implement a high voltage and high capacity lithium secondary battery, by maintaining the structure of the active material while the battery is stable, it can contribute to improve the electrochemical performance, reaction speed and stability of the battery.

 However, although a battery to which the overlithium positive electrode active material and the silicon-based negative electrode active material are simultaneously applied is illustrated, the functional additive may be applied to a battery to which any electrode active material is applied to perform the above function.

 In this regard, in another embodiment of the present invention, a reduction decomposition type additive, including one of fluoroethylene carbonate (FEC) and vinylene carbonate (VC), or a combination thereof; An oxidative decomposition type additive comprising a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a mixture thereof; And an additive, including a semi-ungung additive, which is a compound containing a silyl group, to provide an electrolyte additive for a lithium secondary battery.

[Formula 1]

상기 화학식 1 및 2의 구체적인 사항은 전술한 바와 같아 생략한다. 기능성 첨가제를 이루는 3종의 첨가제 조성 [Formula 2]

Specific details of Chemical Formulas 1 and 2 are omitted as described above. Three kinds of additive composition which make up functional additive

 In the functional additive, the weight ratio of the reduction decomposition additive: oxidative decomposition additive, may be 5: 2 to 12: 0.05, the weight ratio of the reduction decomposition additive: semi-ungsung additive, may be 5: 5 to 12: 0.1 have.

 This means a weight ratio in which each additive in the functional additive can perform an appropriate function.

 Hereinafter, each of the three additives constituting the functional additive will be described in detail.

 Functions and Types of Reductively Degradable Additives and Oxidatively Degradable Additives The reductively degradable additives include fluoroethylene carbonate (FEC) and vinylene carbonate (VC). It has a lower LUMO (Lowest Unoccupied Molecular Orbital) energy than the organic solvent used, and thus has a relatively high tendency to reduce decomposition.

 Accordingly, the reduction decomposition additive may be reduced decomposition before the organic solvent in the electrolyte when the lithium secondary battery is driven, thereby forming a stable protective film and a polymer protective film based on lithium fluoride (LiF) on the surface of the negative electrode. .

 On the other hand, the oxidative decomposition type additive is at least one or more of the above-mentioned material,

 For example, it may be one or more of the materials shown in FIG. 2, but as described above, it generally has a relatively low Occupied Molecular Orbital (HOMO) energy than the lithium salt used in the electrolyte,

 When the lithium secondary battery is driven, it is oxidized and decomposed before the lithium salt in the electrolyte, and a material capable of forming a stable protective film on the surface of the positive electrode.

In other words, the reduction decomposition additive and the oxidative decomposition additive may be reduced or oxidatively decomposed before the organic solvent or the lithium salt in the electrolyte to form a solid electrolyte interface (SEI) on the surface of each electrode. have. The solid electrolyte interface (SEI) formed on the surface of each of the formed electrodes performs a function of stably protecting each of the electrodes without acting as a resistance of the battery. Direct contact with the surface of each electrode can be prevented.

 Functions and Types of Semi-Hung Additives

 On the other hand, the semi-ungpung additive may include a silyl group as described above, it is possible to cause the silyl group to remove the moisture in the electrolyte.

 By this water removal function, it is possible to generally suppress the hydrolysis of lithium salts in the electrolyte. Not only this, even if lithium salt in the domestic electrolyte is hydrolyzed to produce an acidic substance (for example, HF, etc.), the acidic substance is formed by the oxidative decomposition product of the semi-finished additive and neutralization reaction of the acidic substance. May be optionally removed. In addition, the semiunghyeong additive also has the side effect of forming a stable film on the surface of the positive electrode together with the oxidative decomposition type additive.

 As described above, the semi-heung type additive is not particularly limited as long as it is a compound containing a silyl group, but it is tris (trimethylsilyl) phosphite

(Tris (trimethylsilyl) pho sphite (TMSP), tris (trimethylsilyl) methane (tris ylsilyl) metane, T-TMSM) bis (trimethylsilyl) methane (Bis (trimethylsilyl) metliane, B-BMSM), tris Trimethylsilyl amine (T-TMSA), bis (trimethylsilyl) amine (B is (trimethylsilyl) amine, B-TMSA), bis (trimethylsilyl) sulfide bis (trimethylsilyl) sulfide Bis (tmnethylsilyl sulfide, B-TMSSi), bis (trimetylsiloxy) ethane (B-TMSE), bis (trimethylsilylthio) ethane (B-TMSSE), trimethylsilyl eye Trimethylsilyl isotl iocyanate (TMS ITC), Trimethylsilyl isocyanate (TMS IC), trimethyl (phenylselenomethyl) silane (TMPSeS), trimethyl Omethyl) silane Trimethyl (phenylthiomethyl) silane, TMPSS), and N, O-bis (tri Butyl silyl) acetamide (N, 0-Bis (trimethylsilyl) acetamide, B- TMS AI) and bis (trimethylethylsilyl) sulfur diamide (Bis (trimethylsilyl) sulfiir dilimide, B-TMS SDI).

 Manufacturing method of electrolyte additive for lithium secondary battery

 In other embodiments of the present invention, each of the additives described above, namely (1) oxidatively degradable additives alone, and (2) three types of additives: reductively degradable additives, oxidatively degradable additives, and semi-ung additives It proposes a method for producing a functional additive consisting of.

 (1) Method for producing an oxidatively degradable additive alone

 The oxidatively degradable additive alone may be prepared by reacting the compound represented by the following Chemical Formula 3 and a boron raw material.

 In this regard, in another embodiment of the present invention, by reacting the compound represented by the formula (3) and the boron raw material to produce an oxidative decomposition type additive; comprising, a method for producing an electrolyte additive for a lithium secondary battery to provide:

상기 화학식 3에서, Ri 및 R ₂는 각각, 서로 독립적으로, 수소, 치환 또는 비치환된 C1 내지 C8 알킬기, 치환 또는 비치환된 C1 내지 C8 퍼플루오로 알킬기， 치환 또는 비치환된 C6 내지 C30 아렌 (arene)기, 치환 또는 비치환된 C6 내지 C30 퍼플루오로 아렌 (arene)기， CF₃, 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. 또한， A는 리튬, 소듐, 또는 수소이다. 구체적으로, 상기 붕소 원료 물질은， 하기 화학식 4로 표시되는 화합물, 리튬 테트라플루오로보레이트 (Lithium tetrafluoroborate, LiBF₄), 또는 이들의 조합일 수 있다. [화학식 4]

상기 화학식 4에서, R₃ 및 R4는 각각, 서로 독립적으로, 수소, 치환 또는 비치환된 C1 내지 C8 알킬기, 치환 또는 비치환된 C1 내지 C8 퍼플루오로 알킬기, 치환 또는 비치환된 C6 내지 C30 아렌 (arene)기, 치환 또는 비치환된 C6 내지 C30 퍼플루오로 아렌 (arene)기, CF₃, 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. 또한, X는 할로겐 원소 (F, CI, Br, or I), 또는 이들의 조합이다. [Formula ³ ]

In Formula 3, Ri and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene (arene) group, substituted or unsubstituted C6 to C30 perfluoro arene (arene) group, CF ₃ , halogen element (F, CI, Br, or I), or a combination thereof. In addition, A is lithium, sodium, or hydrogen. Specifically, the boron raw material may be a compound represented by the following Chemical Formula 4, lithium tetrafluoroborate (LiBF ₄ ), or a combination thereof. [Formula 4]

In Formula 4, R ₃ and R 4 are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene (arene) group, substituted or unsubstituted C6 to C30 perfluoro arene (arene) group, CF ₃ , halogen element (F, CI, Br, or I), or a combination thereof. In addition, X is a halogen element (F, CI, Br, or I), or a combination thereof.

In addition, the step of preparing the oxidative decomposition type additive; is, in the temperature range of 0 to 150 ^° C, carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, aprotic solvent, or a combination thereof Using a solvent, it may be carried out wet, and the running time may be greater than 0 hours and up to 24 hours.

For example, the oxidative decomposition type additive is reacted by reacting boron trifluorolide (BF ₃ , BF ₃ -OEt ₂ ) or lithium tetrafluoroborate (LiBF ₄ ) with the compound represented by Formula 4 above. In this case, carbonate solvents such as EC, DMC, EMC, PC, and organic solvents such as diethyl ether, pentane, and hexane may be used as the reaction solvent.

 Accordingly, in the step of preparing the oxidative decomposition type additive; a compound represented by the following formula (1), a compound represented by the following formula (2), or a combination thereof may be prepared.

[화학식 2]

상기 화학식 1 및 2의 구체적인 사항은 전술한 바와 같아 생략한다. (2) 3종의 첨가제로 이루어진 기능성 첨가제의 제조 방법 [Formula 1]

[Formula 2]

Specific details of Chemical Formulas 1 and 2 are omitted as described above. (2) Manufacturing method of functional additive which consists of three kinds of additives

 Meanwhile, the functional additive may be prepared by preparing an oxidative decomposition type additive as described above, and then mixing it with a reduction decomposition type additive and a reactive type additive.

 In this regard, in another embodiment of the present invention, preparing a oxidative decomposition type additive by reacting a compound represented by the following Chemical Formula 4 and a boron raw material; And mixing the oxidative decomposition type additive, the reduction decomposition type additive and the reaction type additive, and a method of manufacturing an electrolyte for a lithium secondary battery.

¾ and R 2 are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, Substituted or unsubstituted C6 to C30 perfluoro arene (arene) groups, CF ₃ , halogen elements (F, CI, Br, or 1), or a combination thereof. A is lithium, sodium, or hydrogen.

Specifically, including the boron raw material, the formula The step of producing the oxidative decomposition type additive by reacting with the compound represented by 4 is as described above, and the detailed description thereof is omitted.

 In addition, to satisfy the composition of the above-described functional additives, the oxidative decomposition type additive prepared by the sing-base may simply be mixed with the reduction decomposition type additive and the semi-ung additive.

 Electrolyte for Lithium Secondary Battery

 In other embodiments of the present invention, each of the additives described above, namely (1) oxidatively degradable additives alone, and (2) three types of additives: reductively degradable additives, oxidatively degradable additives, and semi-ung additives It proposes an electrolyte comprising a functional additive consisting of.

 Specifically, each of the functional additives may be added to a basic electrolyte containing an organic solvent and a lithium salt.

 In this regard, in another embodiment of the present invention, an organic solvent; First lithium salt; And an additive; wherein the additive is an oxidative decomposition type additive including a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a combination thereof, and provides an electrolyte for a lithium secondary battery.

 Further, in another embodiment of the present invention, instead of the oxidatively decomposable additive alone, a functional additive consisting of three additives of the reduction decomposition additive, the oxidative decomposition additive, and the reactive additive It provides a lithium secondary electrolyte.

[화학식 2]

싱-기 화학식 1 및 2를 비롯하여, 상기 첨가제들에 관한 설명은 전슬한 바와 같아 생략한다. [Formula 1]

[Formula 2]

The description of the additives, including the single-group formulas (1) and (2), is omitted as is complete.

 Content of Functional Additives in Electrolytes

(1) it can be used to contain, as the additive total weight 100 parts by weight _^0/0 increases, increased from 0.05 to 2% when used alone, only the oxidizing materials decomposable additive.

 (2) On the other hand, the functional additive can be used to be 5 to 19% by weight relative to 100% by weight of the total weight of the electrolyte.

More specifically, the additive total weight to 100% by weight increases, the reduction decomposable additive containing from 5 to 12 parts by weight _^0/0, wherein the decomposable oxide additive

0.05 to 2 parts by weight and contains _^0/0, the reactive additive may be included as 0.1 to 5% by weight. As such, the content of the three additives in the functional additives is limited to the above ranges, respectively, so as to effectively express the respective functions.

 However, when it is less than the lower limit of each of the above ranges, it is difficult to expect the effectiveness of each additive. On the contrary, the non-reflection additive remaining within the upper limit of each of the above-mentioned ranges is generated, thereby causing adverse reactions, thereby lowering battery performance (particularly, high temperature storage performance and high temperature life performance), and relatively low. By reducing the content of the organic solvent and the lithium salt can reduce the function of the basic electrolyte.

Hereinafter, descriptions commonly applied to (1) the case of using only the oxidative decomposition type additive alone and (2) the case of using the functional additive consisting of the three kinds of additives will be described. Types of Lithium Salts and Concentrations in Electrolytes

The lithium salt in the electrolyte may be a crab 1 lithium salt, the first lithium salt is lithium hexafluorophosphate (Lithium hexafluorophosphate, LiPF ₆ ), lithium tetrafluoroborate (Lithium tetrafluoroborate, LiBF ₄ ), lithium perchlorate (Lithium perchlorate, LiC10 ₄ ), Lithium exafluoro arsenate (LiAsF ₆ ), Lithium bis (oxalato) borate (LiBOB), Lithium bisfluorofluorofonimide (Lithium bis (fluorosulfonyl) imide, LiFSI) and lithium fluorooxalateborate (Lithium fluoro (oxalate) borate, LiFOB) may be at least one or more selected from.

In one embodiment of the present invention to be described later, lithium hexafluorophosphate (LiPF ₆ ) was used as the first lithium salt.

 On the other hand, the concentration of the 1-lithium salt in the electrolyte may be 0.1 to 2 M, in this range the electrolyte may have an appropriate conductivity and viscosity, it is possible to effectively move the lithium ions.

 Organic solvent

 The organic solvent is not particularly limited as long as it is an organic solvent generally used in an electrolyte for a lithium secondary battery. However, the organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, aprotic solvent, or a combination thereof. Can be everyday.

 More specifically, the carbonate-based organic solvent may be dimethyl carbonate (dimethyl carbonate, DMC), diethyl carbonate (DEC), dipropyl carbonate (dipropyl carbonte, DPC), methylpropyl carbonate (methylpropyl carbonate, MPC). ), Ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) One or more may be used.

In addition, the ester organic solvent may be methyl acetate (MA), ethyl acetate (EA), n-propyl acetate (n-propyl acetate, n-PA), 1,1-dimethylethyl acetate ( 1,1-dimethylethyl acetate, DMEA), Methyl propionate (MP), ethyl propionate (ΕΡ), γ-butyrolacton (GBL), decanolide, valerolactone, Mevalonolactone (mevalon actone), caprolactone (caprolactone) and the like can be used.

 The ether organic solvent may include dibutyl ether, tetraglyme (tetraethylene glycol dimethyl ether, TEGDME), diglyme (diethylene glycol dimethyl ether, DEGDME), dimethoxy ethane, 2-methyltetra Hydrofuran (2-methyltetrahydroforan), tetrahydrofuran or the like may be used.

 As the ketone-based organic solvent, cyclohexanone, etc. may be used, and as the alcohol solvent, ethyl alcohol, isopropyl alcohol, etc. may be used, and the aprotic solvent may be used. Nitrile dimethylformamide (dimethyl formamide, DMF), such as R-CN (R is a C1 to C10 linear, branched or cyclic hydrocarbon group, and may include a double bond aromatic ring or an ether bond). Amides such as), dioxolanes such as 1,3-dioxolane, and sulfolane, and the like.

 The organic solvents may be used alone or in combination of one or more, and the mixing ratio when using one or more in combination may be appropriately adjusted according to the desired battery performance, which can be widely understood by those skilled in the art. have.

 For example, organic solvents that are ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (dimethyl catbonate, DMC), diethyl carbonate (DEC), or combinations thereof. Can be used.

 At this time, a volume ratio of EC: EMC: DMC = 3: 4: 3 may be applied, but when DMC is used, gas generation may occur in the pouch cell, and in one embodiment of the present invention described below, EC: EMC: DEC = The volume ratio of 2: 5: 3 was applied.

 Functional additives

The composition of the three additives that make up the functional additives, their respective functions and Specific types of materials are as described above. In one embodiment of the present invention described below, a mixture of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) is used as the reduction decomposition additive. Tris (trimethylsilyl) phosphite (TMSP) is used as the semi-ungular additive, and lithium difluoro (maloneto) borate (Lithium difluoro (malonato) is used as the oxidatively decomposable additive. borate, JB-HLiB, lithium difluoro (fluoromalonato) borate (JB-FLiB), lysium difluoro (difluoromaloneto) borate (Lithium difluoro (difluoromalonato) borate (JB-DFLiB) was used.

 Lithium secondary battery

 In other embodiments of the invention, each of the additives described above, namely (1) oxidatively degradable additives alone, and (2) three types of additives: reductively degradable additives, oxidatively degradable additives, and semi-ung additives It proposes a lithium secondary battery to which the functional additive consisting of.

 In this regard, in another embodiment of the present invention, a positive electrode including a lithium-rich positive electrode active material; A negative electrode including a silicon-based negative active material; And an electrolyte comprising an organic solvent, a first lithium salt, and an additive; wherein the additive is an oxidative decomposition type including a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a combination thereof It provides a lithium secondary battery which is an additive.

In another embodiment of the present invention, a positive electrode including a lithium-rich positive electrode active material; A negative electrode including a silicon-based negative active material; And an electrolyte comprising an organic solvent, a crab 1 lithium salt, and an additive, wherein the additive includes a reduction decomposition additive, an oxidative decomposition additive, and a semi-ung additive, wherein the reduction decomposition additive is fluoro. Ethylene carbonate (FEC) and one of vinylene carbonate (vinylene carbonate, VC), or a combination thereof, wherein the oxidative decomposition type additive is a compound represented by the following formula (1), Compounds, or combinations thereof Wherein the semi-finished additive provides a secondary battery which is a compound comprising a silyl group:

[Formula 1]

상기 화학식 1 및 2에 대한 구체적인 사항은 전술한 바와 같아, 상세한 설명을 생략한다. [Formula ² ]

Specific details of Chemical Formulas 1 and 2 are as described above, and detailed description thereof will be omitted.

 In each of the lithium secondary batteries, the lithium-rich positive active material may include a compound represented by the following Chemical Formula 5.

[Formula 5] Li _x Ni _y Mn _z Co _w 0 ₂

 In Formula 5, 1 <χ ≦ 2, 0 <y ≦ l, 0 <ζ ≦ 1, and 0 <w ≦ l. In each of the lithium secondary batteries, the silicon-based negative active material may be a combination of graphite and silicon, a material coated with silicon on the surface of the graphite particles, and a material coated with silicon and carbon simultaneously on the surface of the graphite particles.

The average charging voltage of each lithium secondary battery may be 4.5 V or more. Specifically, as in a general battery, the positive electrode is a positive electrode current collector and the It may include a positive electrode active material layer formed on the positive electrode current collector. Here, the cathode active material layer may include the lithium-rich cathode active material. The lithium-rich positive electrode active material is a compound containing excess lithium than a generally known layered lithium composite metal compound, and may contribute to expressing a high capacity and a high energy density of a battery.

 For example, the lithium-rich positive electrode active material may include a compound represented by Formula 5 below.

[Formula 5] Li _x Ni _y Mn _z Co _w 0 ₂

 In Formula 5, 1 <χ ≦ 2, 0 <y ≦ l, 0 <ζ ≦ 1, and 0 <w ≦ l. Of course, what has a coating layer on the surface of this compound can also be used, or the compound and the compound which have a coating layer can also be used in mixture. The coating layer may include an oxide of a coating element, a hydroxide of a coating element, an oxyhydroxide of a coating element, an oxycarbonate of a coating element, or a hydroxycarbonate of a coating element. The compounds constituting these coating layers may be amorphous or crystalline. As the coating element included in the coating layer, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or a combination thereof may be used. The coating layer forming process may be any method that does not adversely affect the physical properties of the positive electrode active material by using these elements in the compound (for example, any coating method may be used as long as it can be coated by spray coating, immersion method, etc.). Details that will be well understood by those in the field will be omitted.

The positive electrode active material layer also includes a binder and / or a conductive material. The binder adheres positively to the positive electrode active material particles, and also serves to adhere the positive electrode active material to the current collector well, and representative examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, and diacetyl cellulose. , Polyvinylchloride, carboxylated polyvinylchloride, polyvinylfluoride, polymers containing ethylene oxide, polyvinylpyridone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene , Styrene-butadiene rubber, acrylated butadiene rubber, epoxy resin, nylon, etc. However, the present invention is not limited thereto.

The conductive material is used to impart conductivity to the electrode, and any battery can be used as long as it is an electronic conductive material without causing chemical change in the battery. For example, natural graphite, artificial graphite, carbon black, acetylene black, and ketjen. Metal powder, metal fiber, etc., such as black, carbon fiber, copper, nickel, aluminum, silver, etc. can be used, and 1 type (s) or 1 or more types can be mixed and used for electroconductive materials, such as a polyphenylene derivative.

A1 may be used as the current collector, but is not limited thereto. The negative electrode and the positive electrode are each prepared by mixing an active material, a conductive material and a binder in a solvent to prepare an active material composition, and applying the composition to a current collector. Since such an electrode manufacturing method is well known in the art, detailed description thereof will be omitted. As the solvent, n-methyl-2-pyrrolidone (n-methyl-2-pyrrolidone, NMP) may be used, but is not limited thereto.

 Eulry

 The negative electrode may also include a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector, as in a general battery. Here, the negative electrode active material layer may include the silicon-based negative electrode active material.

 In this case, the silicon-based negative active material may be a combination of graphite and silicon, a material coated with silicon on the surface of the graphite particles, and black, a material coated with silicon and carbon simultaneously on the surface of the graphite particles, but is not limited thereto. .

The negative electrode active material layer may further include a binder and / or a conductive material. The binder adheres well to the negative electrode active material particles, and also adheres the negative electrode active material to the current collector. Examples of the binder include polyvinyl alcohol, carboxymethyl cellulose, and carboxymethyl cell. A combination of carboxylmethyl cellulose / polyacrylic acid, ydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, phytovinyl Polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone (polyvinyl pyrrolidone), polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber), a mixture of acrylated styrene-butadiene rubber, styrene-butadiene rubber / carboxymethyl cellulose, epoxy resin or nylon ( nylon) 1 ^' or more may be used, but is not limited thereto.

 The conductive material is used to impart conductivity to the electrode, and may be used as long as it is an electronic conductive material without causing chemical change in the battery. For example, natural graphite, artificial graphite, Carbon-based materials such as carbon black, acetylene black, ketjen black, and carbon fiber; Metal materials such as metal powder or metal fibers such as copper, nickel, aluminum and silver; Conductive polymers such as polyphenylene derivatives; Or an electroconductive material containing these mixture can be used.

The negative electrode current collector may be copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, Polymeric substrates coated with a conductive metal, or combinations thereof, may be used.

 The negative electrode and the positive electrode are each prepared by mixing an active material, a binder, and a conductive material in a solvent to prepare an active material composition, and applying the composition to a current collector. Since such an electrode manufacturing method is well known in the art, detailed description thereof will be omitted.

 Average Layer Voltage of Lithium Secondary Battery

In addition, the average layer voltage of the lithium secondary battery may be 4.5 V or more. This is a high range of voltage that can be expressed as the positive electrode including the over-lithium positive electrode active material and the negative electrode including the silicon-based negative electrode active material are applied, and can be stably maintained by a functional additive included in the electrolyte. additive

 The composition of the oxidatively decomposable additive or the three additives constituting the functional additive, the respective functions, and the specific material types are as described above. In one embodiment of the present invention described below, A mixture of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) is used, and tris (trimethylsilyl) phosphite (TMSP) is used as the semi-additive. As the oxidative decomposition type additive, lithium difluoro (malonate) borate (Lithium difluoro (malonato) borate, JB-HLiB), lithium difluoro (fluoromalonate) borate (Lithium difluoro (fluoromalonato) borate , JB-FLiB), and lithium difluoro (difluoromalonato) borate (JB-DFLiB) were used.

 Hereinafter, preferred examples of the present invention, comparative examples, and evaluation examples in which these are described are described. However, the following examples are only preferred examples of the present invention and the present invention is not limited to the following examples.

 I. Effect of oxidative decomposition additive alone in anode half cell

 A reference electrolyte containing only an organic solvent and a first lithium salt was prepared (Preparation Example 1, Comparative Example 1), and JB-HLiB, JB-FLiB, and JB-DFLiB, which are one of oxidative decomposition additives, were added thereto alone. (Example 1), the effect on JB-HLiB, JB-FLiB, and JB-DFLiB alone was confirmed in the positive electrode half cell.

Preparation Example 1 Preparation of a Reference Electrolyte Containing Only an Organic Solvent and a First Lithium Salt (1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%)

Specifically, the organic solvent is ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (diethyl catbonate, DEC) are 2: ⁵ : ³ (EC: EMC: DEC). Mixed carbonate-based solvents were prepared in a volume ratio of.

In addition, as the first lithium salt, lithium hexafluorophosphate (Lithium hexafluorophosphate, LiPF ₆ ) is used, and the first solvent with respect to the organic solvent is used. It dissolve | dissolved so that the molar concentration of lithium salt might be 1.3 M, and it obtained as the reference electrolyte of manufacture example 1.

 Preparation Example 2 Preparation of Oxidative Decomposition Additives (JB-HLiB, JB-FLiB, JB-DFLiB) Lithium difluoro (malonato) borate, JB- HLiB), Lithium difluoro (fluoromalonato) borate (Lithium difluoro (fluoromalonato) borate, JB-FLiB), Lithium difluoro (difluoromalonato) borate (Lithium difluoro (difluoromalonato) borate, JB -DFLiB) was prepared.

Specifically, as the compound of Formula 4, lithium malonate (JB-HLiB), lithium fluoromalonate (JB-FLiB), lithium difluoromalonate (JB-DFLiB) are used, BIV OEt ₂ is used as a boron raw material, and as a reaction solvent but using dimethyl carbonate, compound of formula 4: was dissolved in the reaction solvent such that 1 to 10 parts by weight _^0/0 for the common combined with the number of moles of 1, was added the total amount 100% by weight: boron raw material = 1. This solution was reacted for 24 hours at 70 ^° C. to finally obtain an oxidatively decomposable additive (JB-HLiB, JB-FLiB, JB-DFLiB).

 Example 1: When the oxidative decomposition type additive was added to the reference electrolyte of Preparation Example 1

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, JBFLiB 0.7 wt%)

 To the reference electrolyte of Preparation Example 1, an oxidative decomposition type additive of Preparation Example 2 was added and used as the electrolyte of Example 1.

Specifically, the electrolyte a total weight of about (100 parts by weight ⁰ /.), Wherein the oxidation decomposable additives JB-HLiB, JB-FLiB, JB-DFLiB is contained 1.0 wt. _^0/0, the reference electrolyte in Production Example 1 based on The electrolyte was made.

 The electrolyte thus prepared was referred to as Example 1, and is represented as "1.0% JB-HLiB, 1.0% JB-FLiB, 1.0% JB-DFLiB" for convenience in FIG. 3.

 (2) fabrication of a lithium secondary battery

 Using the electrolyte of Example 1, a lithium secondary battery was produced.

Liu7Nio.nMno.5Coo.nO2 is used as the overlithium cathode active material, Increased with a binder (PVDF) and a conductive material (Super P) such that the ratio 80:10:10 (base sequence, the positive electrode active material: conductive material: binder) n- ^{methyl-2-pyrrolidone} avoid (n-methyl- ² -pyrrolidone , NMP) solvent was homogeneously mixed.

The composite including the overlithium positive electrode active material was evenly applied to an aluminum (A1) current collector, pressed in a roll press, and vacuum dried at 110 ^° C. vacuum for 2 hours to prepare a negative electrode. At this time, the electrode density was to have 2.5g / cc.

 The prepared anode was used as a working electrode, and Li metal ^ OO ^ m) was used as a reference electrode. Between the prepared anode and Li metal, a polyethylene separator was introduced into a battery container, and the electrolyte added with the functional additive. Was injected to produce a lithium secondary battery in the form of a 2032 half-cell according to a conventional manufacturing method.

 Comparative Example 1 When Reference Electrolyte of Preparation Example 1 was Used

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%)

 The reference electrolyte prepared in Preparation Example 1 was used as the electrolyte of Comparative Example 1. For reference, in FIG. 3, the electrolyte of Comparative Example 1 is represented by convenience- “Ref”.

 (2) fabrication of a lithium secondary battery

 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte of Comparative Example 1 was used instead of the electrolyte of Example 1.

 Evaluation Example 1: Evaluation of Life Characteristics of Each Lithium Secondary Battery of Example 1 and Comparative Example 1

 About each lithium secondary battery of Example 1 and Comparative Example 1, the normal-life life characteristics after 1 time of chemical conversion layer discharge were evaluated, respectively.

First, during the single layer discharge, each of the lithium secondary batteries was charged to 4.6 V, and constant voltage condition (constant voltage, CV) was applied at 4 · ⁶ V after layer discharge, and the stop condition of this condition was 0.05 C. The discharge applied 2.0V constant current conditions. The rate condition of the chemical layer discharge was Ol C-rate.

When evaluating the ambient temperature life, 4.6 at 25 ^° C for each lithium secondary battery After layering to V, the constant voltage condition (constant voltage, CV) was applied at 4. ⁶ V after charging, and the stopping condition of this condition was 0.05 C, and the discharge was applied to the 2.0 V constant current condition. The lifetime evaluation layer conductivity condition was 0.5 C-rate and the discharge rate condition was 0.5 C-mte, and the results are shown in FIG. 3.

 Referring to Figure 3, the life characteristics of the lithium secondary battery of Example 1 is a comparative example

Notice the improvement over 1. Specifically, in Comparative Example 1, the capacity rapidly decreased after 30 layer discharges, whereas in the case of the electrolyte solution using JB-HLiB, JB-FLiB, and JB-DFLiB of Example 1, after 3 cycles of 36.4%, 87.2%, Capacity maintenance rate improved to 92.3%. In case of the electrolyte using JB-DFLiB, the reversible capacity was lowered, but the capacity retention ratio was the best.

This supports the difference depending on the presence or absence of the oxidative decomposition type additive, and by forming the stable film on the surface of the positive electrode by the oxidative decomposition type additive, it means that the side reaction at the surface of the positive electrode is suppressed and the life characteristics of the battery are improved. do.

 II. Effect of Oxidative Degradation Additive Alone in Cathode Half Cell

 A reference electrolyte containing only an organic solvent and a first lithium salt was prepared (Preparation Example 1, Comparative Example 1), and JB-HLiB, JB-FLiB, and JB-DFLiB, which are one of oxidative decomposition type additives, were added thereto alone. (Example 2), The effect on the JB-HLiB, JB-FLiB, and JB-DFLiB single substance was confirmed in the negative electrode half-sal.

 Example 2 When Oxidative Decomposition Addition was Added to the Reference Electrolyte of Preparation Example 1

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, JBFLiB 0.7 wt%)

 To the reference electrolyte of Preparation Example 1, an oxidative decomposition type additive of Preparation Example 2 was added and used as the electrolyte of Example 2.

Specifically, the electrolyte a total weight of about (100 parts by weight _^0/0), wherein the oxidation decomposable additives JB-HLiB, JB-FLiB, JB-DFLiB is contained 1.0 wt. _^0/0, the reference electrolyte in Production Example 1 based on The electrolyte was made.

Thus prepared electrolyte is Example 2, in Figure 4 for convenience "1.0% JB- HLiB, 1.0% JB-FLiB, 1.0% JB-DFLiB ".

 (2) fabrication of a lithium secondary battery

 The lithium secondary battery was produced using the electrolyte of Example 1.

Graphite as an anode active material is used, and a binder (PVDF) increased ratio of 95: ^5, such that the (anode active material: binder) n- ^{methyl-2-pyrrolidone} to blood-uniform in the ^(n-2 methyl- pyrrolidone, NMP) solvents Mixed.

The composite including the negative electrode graphite active material was evenly applied to a current collector of copper (A1), pressed in a roll press, and vacuum dried at 80 ^° C. vacuum for 2 hours to prepare a negative electrode. At this time, the electrode density was to have 1.2g / cc. The prepared negative electrode was used as a working electrode, and Li metal (700 ffli) was used as a reference electrode. Between the prepared negative electrode and Li metal, a polyethylene separator was introduced into a battery container, and the electrolyte to which the functional additive was added was used. Injecting, to produce a lithium secondary battery in the form of a 2032 half-cell according to a conventional manufacturing method.

 Comparative Example 2: In the case of using the reference electrolyte of Preparation Example 1

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%)

 The reference electrolyte prepared in Preparation Example 1 was used as the electrolyte of Comparative Example 1. For reference, in FIG. 4, the electrolyte of Comparative Example 2 is represented as “Ref” for convenience.

 (2) fabrication of a lithium secondary battery

 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte of Comparative Example 2 was used instead of the electrolyte of Example 2.

 Evaluation Example 2: Evaluation of Life Characteristics of Each Lithium Secondary Battery of Example 2 and Comparative Example 2

 For each of the lithium secondary batteries of Example 2 and Comparative Example 2, the normal temperature life characteristics after one cycle of layer discharge were respectively evaluated.

First, in the case of the single layer discharge, each of the lithium secondary batteries was charged to 0.01 V, and after charging, constant voltage condition (constant voltage, CV) was applied at 0.01 V, and the stop condition of this condition was 0.01 C. 1.0V constant current Conditions were applied. The rate condition of the ignition layer discharge was O. l C-rate.

 When evaluating the shelf life, the lithium secondary battery was charged to 0.01 V at 25 ° C, and after charging, the constant voltage condition (constant voltage, CV) was applied at 0.01 V, and the stop condition of this condition was 0.01 C. 1.0 V constant current conditions were applied. The lifetime evaluation layer conductivity condition was 0.5 C-rate and the discharge rate condition was 0.5 C-rate, and the results are shown in FIG. 4.

 Referring to Figure 4, it can be seen that the life characteristics of the lithium secondary battery of Example 2 is improved compared to Comparative Example 2. Specifically, in Comparative Example 2, the capacity suddenly decreased after 50 layer discharges, whereas in the case of the electrolyte solution using JB-HLiB and JB-FLiB of Example 2, the capacity retention rate was greatly improved to 97.3% and 85.0% after 50 cycles, respectively. It became. In the case of the electrolyte using JB-DFLiB, the life performance is greatly reduced.

This means that the oxidative decomposition type additive not only has excellent negative electrode compatibility but also contributes to the formation of the negative electrode film, thereby preventing side reactions on the negative electrode surface and improving the lifespan characteristics of the battery.

 Judging from the evaluation results of the positive and negative half cells, the JB-FLiB has the best positive / negative compatibility, and the battery life characteristics are improved.

 III. Identification of the effects of additives including FEC, VC, JBFLiB and TMSP in anode half cell

 A reference electrolyte comprising only an organic solvent and a first lithium salt was prepared (Preparation Example 1), and two or more additives of FEC, VC, JBFLiB, and TMSP were added thereto (Example 3, Comparative Example 3), FEC The effect of additives including VC, JBFLiB, and TMSP was confirmed in the anode half cell.

 Example 3: When FEC, VC, JBFLiB, and TMSP were added to the reference electrolyte of Preparation Example 1

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, FEC 5 wt%, VC 0.5 wt%, JBFLiB 0.5 wt%, TMSP 0.2 wt%)

Specifically, the reduction decomposition additive is fluoroethylene carbonate (fluoro ethylene carbonate, FEC) and vinylene carbonate (VC) are used, and as an oxidative decomposition type additive, lithium difluoro (fluoromalonate) borate obtained in Preparation Example 2 (Lithium) Difluoro (fluoromalonato) borate (JBFLiB) was used, and as the semi-ung additive, tris (trimethylsilyl) phosphite (Tris (trimethylsilyl) phosphite (TMSP)) was used, and these additives were added to the Preparation Example 1 reference electrolyte.

At this time, the electrolyte a total weight of about (100 parts by weight _^0/0), FEC of the reduction decomposable additive containing 5 parts by weight _^0/0, VC was 0.5% by weight, JBFLiB of the oxidation decomposable additive 0.5 _^0/0 is included, the TMSP banung type additive is contained 0.2 _^0/0, the reference electrolyte in Preparative example 1 was such that an amount of glass.

 For reference, the electrolyte of Example 3 is shown as "UNIST-3" in FIG. 5 for convenience.

 (2) fabrication of a lithium secondary battery

 A lithium secondary battery in the form of a 2032 half-cell was manufactured in the same manner as in Example 1, except that the electrolyte of Example 3 was used instead of the electrolyte of Example 1.

 Comparative Example 3: When FEC and VC were added to the reference electrolyte of Preparation Example 1

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, FEC 5 wt%, VC 0.5 wt%) In the reference electrolyte of Preparation Example 1, FEC, which was the reduction decomposition type additive,

But adding only VC, the comparison of the reducing decomposable additive for the entire electrolyte weight (100 weight%) FEC to include 5 wt%, VC is contained 0.5 Increased _^0/0, the reference electrolyte in Preparative Example 1 part glass The electrolyte of Example 3 was prepared.

 For reference, the electrolyte of Comparative Example 3 is denoted as "Re for convenience. (2) Fabrication of a lithium secondary battery

 A lithium secondary battery was manufactured in the same manner as in Example 3, except that the electrolyte of Comparative Example 3 was used instead of the electrolyte of Example 3.

 Evaluation Example 3 Evaluation of High Rate Discharge Characteristics for Each Lithium Secondary Battery of Example 3 and Comparative Example 3

For each lithium secondary battery of Example 3 and Comparative Example 3, one chemical composition After charging and discharging, the charging rate was fixed to C / 5, and the discharge rate was changed to C / 5, C / 2, 1C, 3C, 7C, 20C, and C / 5 to evaluate high rate discharge characteristics, respectively. Evaluation was performed for each three cycles for each discharge rate, and FIG. 5 is a graph showing the discharge capacity according to the rate. Referring to FIG. 6, it can be seen that the discharge capacity at a high rate of the lithium secondary battery of Example 3 is significantly improved than that of Comparative Example 3.

 Through this, reduction decomposition additives (FEC, VC) form a stable film on the surface of the cathode, oxidative decomposition type additive (JBFLiB) forms a film with excellent ion conductivity on the surface of the anode to facilitate the movement of lithium, The effect that the type additive (TMSP) removes HF to improve the stability of the anode interface can be seen once again.

 IV. Identification of the effects of additives including FEC, VC, JBFLiB and TMSP in OLO / Si-C full cells

 For a reference electrolyte containing only an organic solvent and a first lithium salt (Preparation Example 1), an electrolyte in which only a reductive decomposition additive and a semiamorphous additive were added (Comparative Example 4), as well as a oxidative decomposition as well as a reductive decomposition additive and a semiungular additive An electrolyte (Example 4) to which a type additive was also added was prepared, and the effect on JBFLiB was confirmed in a full cell.

 Comparative Example 4: In the case of using an electrolyte in which an organic solvent and a first lithium salt are added with a reduction decomposition type additive and a semi-ung additive type

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, FEC 5 wt%, VC 0.5 wt, TMSP

0.2 wt%)

 To the reference electrolyte of Preparation Example 1, a reduction decomposition type additive and a semiaung form additive were added.

 More specifically, fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are used as reduction decomposition type additives, and tris (trimethylsilyl) phosphite (Tris (trimethylsilyl) is used as a semi-additive additive. ) phosphite, TMSP) was used.

At this time, for the Electrolyte total weight (100 weight%), the FEC of the reduction decomposable additive containing 5 parts by weight _^0/0, VC is 0.5 _^0/0, wherein the additive type banung TMSP is included 0.2% by weight, and the reference electrolyte of Preparation Example 1 was to be included as a balance.

 The electrolyte thus prepared is referred to as Comparative Example 4, and is labeled "Ref" for convenience in FIGS. 6 to 8.

 (2) fabrication of a lithium secondary battery

 The lithium secondary battery was produced using the electrolyte of the comparative example 4.

 Specifically, a silicon-based negative electrode active material is a material coated with silicon and carbon on the surface of the graphite particles at the same time, the diameter is 10 to 20. Further, the mixture was uniformly mixed in distilled water (¾0) so that the weight ratio of the binder (SBR-CMC) and the conductive material (Super P) was 96: 1: 3 (base order, negative electrode active material: conductive material: binder).

The composite including the silicon-based negative active material was evenly applied to a copper (Cu) current collector, and then vacuum dried for 2 hours in a 110 ^° C. vacuum oven to prepare a negative electrode. At this time, the electrode density was to have 1.2 to 1.3 g / _CC .

On the other hand, as a lithium lithium positive electrode active material Liu ₇ Ni ₀ . ₁₇ Mno. ₅ Coo.i ₇ 0 ₂ , so that the weight ratio of the binder (PVDF) and the conductive material (Super P) is 90: 5: 5 (base sequence _: positive electrode active material: conductive material: binder) n-methyl- ² Homogeneously mixed in -pyrrolidone (n-methyl- ² -pyrrolidone, NMP) solvent.

The composite including the perlithium cathode active material was evenly applied to an aluminum (A1) current collector, and then pressed in a press, followed by vacuum drying at 110 ^° C. vacuum for 2 hours to prepare a negative electrode. At this time, the electrode density was set to have 2.5 g / _CC .

 Between each of the prepared negative electrode and positive electrode, a polyethylene separator is introduced into a battery container, the electrolyte of Comparative Example 4 is injected, and a lithium secondary battery in the form of a 2032 full-cell according to a conventional manufacturing method. Was produced.

 Example 4: When JBFLiB was added to the electrolyte of Comparative Example 4

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, FEC 5 wt%, VC 0.5 wt%, JBFLiB 0.2-0.7 wt%, TMSP 0.2 wt%) Specifically, as an oxidative decomposition type additive, lithium difluoro (fluoromalonato) borate (JBFLiB) obtained in Preparation Example 2 was used, and this was added to the electrolyte of Comparative Example 4. .

At this time, the electrolyte a total weight of about (100 parts by weight _^0/0), FEC of the reduction decomposable additive containing 5 parts by weight _^0/0, VC was 0.5% by weight, JBFLiB of the oxidation decomposable additive 0.2 _^0/0 , was adjusted to 0.5 and contains _^0/0, or 0.7 wt. _^0/0, the TMSP banung type additive is contained 0.2 _^0/0, the reference electrolyte in the Preparation example 1 is an amount of glass.

 For reference, the electrolyte of Example 4 in FIGS. 6 to 8 is labeled as "UNIST-3" for convenience, and the oxidative decomposition type additive content is indicated in parentheses (0.2% JB-F, 0.5% JB-F, 0.7%). JB-F).

 (2) fabrication of a lithium secondary battery

 A lithium secondary battery was manufactured in the same manner as in Comparative Example 4, except that the electrolyte of Example 4 was used instead of the electrolyte of Comparative Example 4.

 Evaluation Example 4: Evaluation of life characteristics of the lithium secondary batteries of Example 4 and Comparative Example 4

 For each of the lithium secondary batteries of Example 4 and Comparative Example 4, the phase after one chemical layer discharge was evaluated for the life characteristics, respectively.

First, during the single-time charging and discharging, each lithium secondary battery was layered at 4.55 V, and after charging, a constant voltage condition (constant voltage, CV) was applied at 4. ⁵ 5 V. The stopping condition of this condition was 0.02 C. , The discharge was applied to 2.0V constant current conditions. The rate condition of the chemical layer discharge was Ol C-rate.

 After the above-mentioned single layer discharge, before the evaluation of the normal temperature life characteristics, the layer discharge was further performed three times in order to secure the life stability. Specifically, each lithium secondary battery was layered at 4.55V, and after the layering, a constant voltage condition (constant voltage, CV) was applied at 4.55V, and the stop condition of this condition was 0.05 C, and the discharge was applied with a 2.0V constant current condition. . The layer discharge rate condition was 0.2 C-rate.

4.55 at 25 ^° C for each lithium secondary battery when the ambient temperature life evaluation After charging to V, constant voltage condition (constant voltage, CV) was applied at 4.55V after layer discharge, and the stop condition of this condition was 0.05C, and the discharge was applied to 2.0V constant current condition. The lifetime evaluation rate condition was 0.5 C-rate and the results are shown in FIG. 6.

 Referring to Figure 6, it can be seen that the life characteristics of Example 4 that is higher than the comparative example 4.

 Specifically, when only two additives of the reduction decomposition type additives (FEC, VC) and the reactive type additives (TMSP) are added to the lithium salt and the organic solvent (Comparative Example 4), the discharge capacity retention rate is only 9.5%, By adding the decomposition type additive (JBFLiB) (Example 4) it can be seen that the discharge capacity retention rate is increased to 43.3% or more, up to a maximum of 74.5%.

These results support the effects of the addition of oxidative degradation additives (JBFLiB). More specifically, the reduction decomposition additives (FEC, VC) form a stable film on the surface of the cathode, and the reactive additives (TMSP) react with HF and H ₂ 0 in the electrolyte to suppress side reactions that degrade the performance of the cell. In addition, when the oxidative decomposition type additive (JBFLiB) forms a stable film on the surface of the anode, side reactions of the electrolyte are further suppressed and lifespan characteristics are improved.

 In this regard, referring to FIG. 6, it can be seen that as the content of the oxidative decomposition type additive in the electrolyte increases, the discharge capacity maintenance also increases.

 This means that it is possible to further improve the life of the battery by appropriately controlling the content of the oxidatively decomposable additive in the electrolyte and the content of the reductively decomposed additive and the semi-ungky additive.

 Evaluation Example 5: Evaluation of Silver Silver Self-Discharge Characteristics of Each Lithium Secondary Battery of Example 4 and Comparative Example 4

 For each lithium secondary battery of Example 4 (0.5% JB-FLiB), and Comparative Example 4,

After one-time layer discharge and layer discharge, the cells were stored at 60 ° C for 20 days and the self-discharge characteristics of the full cell were evaluated. First, during the single layer discharge, each lithium secondary battery was charged to 4.55 V, and after the layer discharge, a constant voltage condition (constant voltage, CV) was applied at 4.55 V, and the stop condition of this condition was 0.02 C. A 2.0V constant current condition was applied. The rate condition for Mars layer discharge is 0.1 C- rate. In order to evaluate self-discharge, layer discharge was performed once more at room temperature. The layer exhibition conditions were performed in the same manner as in the chemical conversion. The open circuit voltage (OCV) of the full cell using the electrolyte solution of Example 1 and Comparative Example 1 was measured. After 20 days of storage at 60 degrees, the discharge was carried out under the conditions of the Mars discharge, and the capacity retention rate was measured.

 7 to 8, it can be seen that the open circuit voltage reduction width of the lithium secondary battery of Example 4 is smaller than that of Comparative Example 4, and the capacity retention rate (dotted line) is greatly improved.

 Specifically, the higher temperature self-discharge characteristics of the lithium secondary battery of Example 4 than that of Comparative Example 4 are expressed by the fact that the oxidative decomposition type additive (JBFLiB) forms a stable film on the surface of the positive electrode, thereby suppressing the dissolution of the transition metal. It is understood. In Comparative Example 4, since the transition metal of the positive electrode did not effectively inhibit elution, a decrease in capacity due to the loss of the transition metal occurred in the positive electrode, and the negative electrode accelerated deterioration of the negative electrode interface as the transition metals deposited on the negative electrode surface. Is generated to deteriorate the high temperature self-discharge characteristics.

 V. Determination of the Effect of Additives Containing FEC, VC, JBFLiB and TMSP in LCO / Graphite Full Cells (Preparation Example 1) Reaction with Reductively Degradable Additives on Reference Electrolytes Containing Only Organic Solvents and First Lithium Salts An electrolyte in which only a type additive was added (Comparative Example 4), an electrolyte in which a oxidative decomposition type additive was added (Example 4) as well as a reduction decomposition type and a semi-ungung type additive, and the effect on JBFLiB was confirmed in a full cell.

 Comparative Example 5: In the case of using an electrolyte in which an organic solvent and a first lithium salt were added with a reduction decomposition type additive

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, FEC 5 wt%, VC 0.5 wt) To the reference electrolyte of Preparation Example 1, a reduction decomposition type additive and a semi-ung additive were added. .

More specifically, the reduction decomposition type additive is fluoroethylene Carbonate (fluoroethylene carbonate, FEC) and vinylene carbonate (vinylene carbonate, VC) were used.

At this time, and so to the electrolyte the total weight (100 weight%), FEC of the reduction decomposable additive containing 5 parts by weight _^0/0, VC is 0.5 _^0/0, the reference electrolyte in the Preparation Example 1 is an amount of glass .

 The electrolyte thus prepared is referred to as Comparative Example 5, and is labeled "RFV" for convenience in FIGS. 9 to 10.

 (2) fabrication of a lithium secondary battery

 A lithium secondary battery was produced using the electrolyte of Comparative Example 5.

 Specifically, natural graphite was used as the graphite anode active material, and its diameter was 10 to 20. Further, the mixture was uniformly mixed in a middle water (¾0) solvent such that the weight ratio of the binder (SBR-CMC) and the conductive material (Super P) was%: 1: 3 (base order, negative electrode active material: conductive material: binder).

The composite including the graphite negative electrode active material was evenly applied to a copper (Cu) current collector, and then vacuum dried for 2 hours at 110 ^° C vacuum Aubon to prepare a negative electrode. At this time, the electrode density was to have 1.2 to 1.3 g / cc.

On the other hand, LiCo0 ₂ is used as the positive electrode active material, so that the weight ratio of the binder (PVDF) and the conductive material (Super P) is 96: 2: 2 (base order, positive electrode active material: conductive material: binder) n-methyl- It was homogeneously mixed in a ^2- pyridone (n- methyl- ² -pyrrolidone, NMP) solvent.

 The composite including the positive electrode active material was evenly applied to an aluminum (A1) current collector, and then pressed in a press, followed by vacuum drying at 1 HTC vacuum Aubon for 2 hours to prepare a negative electrode. At this time, the electrode density was to have 3.0g / cc to 3.5g / cc.

 Between each of the prepared negative electrode and positive electrode, a polyethylene separator is introduced into a battery container, the electrolyte of Comparative Example 4 is injected, and a lithium secondary battery in the form of 2032 full-cell according to a conventional manufacturing method. Was produced.

Example 5: When TMSP and JBFLiB were added to the electrolyte of Comparative Example 5 (1) Preparation of electrolyte (1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%, FEC 5 wt%, VC 0.5 wt%, JBFLiB 0.5 wt%, TMSP 0.2 wt%)

 Specifically, as the oxidative decomposition type additive, lithium difluoro (fluoromalonato) borate (JBFLiB) obtained in Preparation Example 2 and tris (trimethylsilyl) phosphite which is a semi-ung additive (Tris (trimethylsilyl) phosphite, TMSP) was added to the electrolyte of Comparative Example 5.

At this time, for the Electrolyte total weight (100 parts by weight _^0/0), wherein during reduction decomposable additives FEC 5 weight _^0/0, VC is contained lead 5% by weight, JBFLiB of the oxidation decomposable additive 0.7 Increased ⁰ / ₀ is included, the TMSP banung type additive is contained 0.2 _^0/0, the reference electrolyte in Preparative example 1 was such that an amount of glass.

 For reference, the electrolyte of Example 5 in FIGS. 9 to 10 is labeled as "UNIST-3" for convenience, and the oxidative degradation additive content is indicated in parentheses (0.7% JB-F).

 (2) fabrication of a lithium secondary battery

 A lithium secondary battery was manufactured in the same manner as in Comparative Example 5, except that the electrolyte of Example 5 was used instead of the electrolyte of Comparative Example 5.

 Evaluation Example 6: Evaluation of Life Characteristics of Each Lithium Secondary Battery of Example 5 and Comparative Example 5

 About each lithium secondary battery of Example 5 and the comparative example 5, the normal temperature and high temperature life characteristics after 1 time of chemical conversion layer discharge were evaluated, respectively.

First, during the single layer discharge, each lithium secondary battery was layered to 4.35 V, and after charging, a constant voltage condition (constant voltage, CV) was applied at 4. ³ 5 V. The stopping condition of this condition was 0.02 C. , The discharge was applied to 2.7V constant current conditions. The rate condition of the chemical layer discharge was Ol C-rate.

After the above-mentioned single layer discharge, before the evaluation of the normal temperature and high temperature life characteristics, in order to ensure the stability of life, further three thin layer discharge was performed. Specifically, each lithium secondary battery layered to 4.35V, and after the layered, the constant voltage condition (constant voltage, CV) was applied at 4.35V, the stop condition of this condition was 0.05C, and the discharge was applied to the 2.7V constant current condition. . The layer discharge rate condition was 0.2 C-rate. When evaluating the room temperature and high temperature life, for each lithium secondary battery

Layered at 4.35 V at 25 ^° C., constant voltage condition (CV) was applied at 4.35 V after layer deposition. The stop condition was 0.05 C, and the discharge was applied at 2.7 V constant current. The life evaluation rate condition was 0.5 C-rate and the results are shown in FIGS. 9 to 10.

 9 to 10, room temperature and high temperature life characteristics of Example 5 which is higher than Comparative Example 5 can be confirmed.

 Specifically, in the case where only two additives, a reduction decomposition type additive (FEC, VC) and a semi-ung additive type (TMSP), are added to the lithium salt and the organic solvent (Comparative Example 5) While 66.5% and 60.6% respectively, the addition of the oxidative decomposition type additive (JBFLiB) (Example 5) It can be seen that the discharge capacity retention rate is improved to 83.4%, 73.3%.

These results support the effects of the addition of oxidative degradation additives (JBFLiB). More specifically, the reduction decomposition additives (FEC, VC) form a stable film on the surface of the cathode, and the reactive additives (TMSP) react with HF and H ₂ 0 in the electrolyte to suppress side reactions that degrade the performance of the cell. In addition, when the oxidative decomposition type additive (JBFLiB) forms a stable film on the surface of the anode, side reaction of the electrolyte is further suppressed, and lifespan characteristics are improved.

 The anodic interfacial stabilization of oxidative decomposition additive JB-FLiB can be confirmed by comparing the evaluation of LCO / Graphite full cell and OLO / SiC full cell. .

 VI. Confirmation of HF removal effect of TMSP additive

 For the reference electrolyte containing only the organic solvent and the first lithium salt (Preparation Example 1), an electrolyte in which only a semi-ungwoong additive was added (Comparative Example 6) was prepared, and the effect on the HF removal of TMSP was confirmed.

 Comparative Example 6: Electrolyte Solution Using Organic Solvent and First Lithium Salt

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.%)

 The same electrolyte as the reference electrolyte of Preparation Example 1 was used.

Thus prepared electrolyte is referred to as Comparative Example 6, for convenience in FIG. Marked with "Without additive".

 Example 6: Electrolyte Solution to which Semiunghyeong additive TMSP was added to organic solvent and first lithium salt

 (1) Preparation of Electrolyte

(1.3 M LiPF ₆ in 2: 5: 3 (EC: EMC: DEC) vol.% + 0.5% TMSP)

An electrolyte solution was prepared by adding 0 · ⁵ % of tris (trimethylsilyl) phosphite (TMSP), which is a semi-ung additive, to the reference electrolyte of Preparation Example 1.

Evaluation Example 7 HF Removal Effect of Example 6, and Comparative Example 6 ¹⁹ F NMR Analysis Each of the organic electrolyte and the reference electrolyte prepared in Comparative Examples 6 and 6 was separated by about 0.4 mL using a micro pipette. After soaking in each vial, add about 0.02 mL of distilled water, mix, and store for about 72 hours.

 Then, add about o.4 mL of tetrahydrofuran D-8 (Tetrahydrofuran-D8, D 99.5%) to each vial, mix, and place it in an NMR tube, seal with parafilm, and store it for about 3 hours. It was.

Finally, each vial was taken out of the simple glovebox, and ^{1 g} F-NMR and ³¹ P-NMR were measured, and the results are shown in FIG. 11. In Fig. 11, the ¹⁹ F-NMR graph shown on the left side is for the reference electrolyte, and the graph shown on the right is for the organic electrolyte prepared in Example 6.

 Referring to FIG. 11, unlike Comparative Example 6, it may be confirmed that HF is hardly detected in the organic electrolyte of Example 6. Therefore, it can be seen that the organic electrolyte solution containing TMSP shows an excellent effect on the removal of acid, for example, HF. The present invention is not limited to the above embodiments, but may be manufactured in various forms, and a person skilled in the art to which the present invention pertains has another specific form without changing the technical spirit or essential features of the present invention. It will be appreciated that the present invention may be practiced as. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

[Explanation of code] 100: lithium secondary battery 112: negative electrode

113: separator 114: anode

120: battery container 140: sealing member

Claims

Claims Claim 1 An electrolyte additive for a lithium secondary battery, which is an oxidative decomposition type additive comprising a compound represented by the following formula (1), a compound represented by the following formula (2), or a mixture thereof: [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,  And ¾ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, Substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , halogen element (F, CI, Br, or 1), or a combination thereof,  n is 1 or 2, and m is 1 or 2.  [Claim 2]  The method of claim 1,  The oxidative decomposition type additive,  Lithium difluoro (malonato) borate (JB-HLiB), Lithium difluoro (fluoromalonato) borate (JBFLiB), Lithium difluoro (di Fluoromalonato) borate (lithium difluoro (difluoromalonato) borate (JB-DFLiB), lithium difluoro (bromomalonato) borate (lithium difluoro (bromomalonato) borate), lithium difluoro (chloromalonato) borate ( lithium difluoro (chloromalonato) borate), lithium difluoro (iodomalonato) borate, lithium difluoro (phenylmalonato) borate, lithium difluoro Fluoro (perfluoromalonato) borate, lithium difluoro (trifluoromethylmalonato) borate, lithium difluoro (trifluoromethylmalonato) borate, lithium difluoro (trifluoromethylmalonato) borate Lithium bis (malonato) borate, lithium bis (fluoromalonato) borate, lithium bis (difluoromalonato) borate (lithium bis (difluoromalonato) borate ), Lithium bis (phenylmalonato) borate, lithium bis (perfluoromalonato) borate, lithium bis (trifluoromethylmalonato) borate (lithium bis (phenylmalonato) borate) lithium bis (trifluoromethylmalonato) borate), which is at least one selected from  Electrolyte additive for lithium secondary battery.  [Claim 3] By reacting the compound represented by the formula (3) and the boron raw material, To prepare a oxidative decomposition additive; comprising;  Process for preparing electrolyte additive for lithium secondary battery: [Formula 3]

In Chemical Formula 3, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or a combination thereof,  A is lithium, sodium, or hydrogen.  [Claim 4]  The method of claim 3, wherein The boron raw material is a compound represented by the following formula ( ₄ ), lithium tetrafluoroborate (Lithium tetrafluoroborate, LiBF ₄ ), or a combination thereof,  Process for preparing electrolyte additive for lithium secondary battery:

In Chemical Formula 4, R ₃ and R 4 are each, independently of one another, hydrogen, substituted or unsubstituted C1 to C8 alkyl group, substituted or unsubstituted C1 to C8 perfluoro alkyl group, substituted or unsubstituted C6 to C30 arene group, substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , Halogen element (F, CI, Br, or I), or a combination thereof,  X is a halogen element (F, CI, Br, or I), or a combination thereof.  [Claim 5]  The method of claim 3, wherein  Preparing the oxidative decomposition type additive;  A method for producing an electrolyte additive for a lithium secondary battery, which is carried out wet using a carbonate, ester, ether, keron, alcohol, aprotic solvent, or a combination thereof.  [Claim 6]  The method of claim 3,  Preparing the oxidative decomposition type additive; What is carried out in the temperature range of 0 to 150 ^° C,  The manufacturing method of the electrolyte additive for lithium secondary batteries.  [Claim 7]  The method of claim 3, wherein  Preparing the oxidative decomposition type additive,  It is performed less than 0 hours and less than 24 hours ，  The manufacturing method of the electrolyte additive for lithium secondary batteries.  [Claim 8]  The method of claim 3, wherein  In the step of preparing the oxidative decomposition type additive, A compound represented by the following formula (1), a compound represented by the following formula (2) _: or a mixture thereof is prepared,  The manufacturing method of the electrolyte additive for lithium secondary batteries. [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,  And ¾ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or a combination thereof,  n is 1 or 2 and m is 1 or 2.  [Claim 9]  Reduction decomposition additives, including one of fluoroethylene carbonate (FEC) and vinylene carbonate (VC), or a combination thereof; A compound represented by the following formula, a compound represented by the following formula (2), Oxidative decomposition type additives including these mixtures; And  Including a reactive additive which is a compound containing a silyl group  Electrolyte Additives for Lithium Secondary Batteries: [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,  Xi and ¾ are each, independently of one another, hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof, ¾ and R 2 are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or a combination thereof, n is 1 or 2, and m is 1 or 2.  [Claim 10]  The method of claim 9,  Reduction decomposition additive: The weight ratio of the oxidative decomposition additive is 5: 2 to 12: 0.05,  Electrolyte additive for lithium secondary battery. 【Claim 11】  The method of claim 9,  Reducing decomposition type additive: The weight ratio of the semi-finished additive is 5: 5 to 12: 0.1,  Electrolyte additive for lithium secondary battery.  [Claim 12]  According to claim 19,  The oxidative decomposition type additive, Lithium difluoro (malonato) borate (JB-HLiB), Lithium difluoro (fluoromalonato) borate (JBFLiB), Lithium dipoloro (di Fluoromalonato) borate (lithium difluoro (difluoromalonato) borate (JB-DFLiB), lithium difluoro (bromomalonato) borate), lithium difluoro (chloromalonato) borate (lithium difluoro (chloromalonato) borate), lithium difluoro (iodomalonato) borate, lithium difluoro (phenylmalonato) borate (lithium difluoro (p enylmalonato) borate), lithium Difluoro (perfluoromalonato) borate, lithium difluoro (trifluoromethylmalonato) borate, lithium difluoro (trifluoromethylmalonato) borate, Lithium bis (NATO words) borate (lithium bis (malonato) borate), lithium bis (NATO words fluorophenyl) borate (lithium bis (fluoromalonato) borate, lithium bis (difluoromalonato) borate, lithium bis (phenylmalonato) borate, lithium bis (perfluoromalolo) At least one selected from lithium bis (perfluoromalonato) borate, and lithium bis (trifluoromethylmalonato) borate (lithium bis (trifluoromethylmalonato) borate)  Electrolyte additive for lithium secondary battery.  [Claim 13]  The method of claim 9,  The reactive additive is.  Tris (trimethylsilyl) phosphite (TMSP), Tris (trimethylsilyl) methane (T-TMSM), Bis (trimethylsilyl) methanee (B-) BMSM), Tris (trimethylsilyl) amine (T-TMSA), Bis (trimethylsilyl) amine (Bis (trimethylsilyl) amine, B-TMSA), Bis (trimethylsilyl) sulphi J Bis (trimethylsilyl Sulfide Bis (trimethylsilyl) sulfide, B-TMSSi), bis (trimethylsilyl) ethane (B is (trimetyls ilo xy) ethane, B-TMSE), bis (trimethylsilylthio) ethane (Bis (trimethylsilylthio) ethane. B-TMSSE), Trimethylsilyl isothiocyanate (TMS ITC), Trimethylsilyl isocyanate (TMS IC), Trimethyl (phenylselenomethyl) silane, TMPSeS), Trimethyl (phenylthiomethyl) Silane Trimethyl (phenylthiomethyl ) silane, TMPSS), and N, O-bis (trimethylsilyl) acetamide (^ O-BisOimethylsilyDacetamide, B-TMS AI), bis (trimethylethylsilyl) sulfur diamide (Bis (trimethylsilyl) sulfor dilimide, B-TMS At least one selected from SDI),  Electrolyte additive for lithium secondary battery.  [Claim 14] Preparing a oxidative decomposition type additive by reacting the compound represented by Formula 3 and a boron raw material; And And mixing the oxidative decomposition type additive with a reduction decomposition type additive and a semi-opening additive.  The reduction decomposition additive includes one of fluoroethylene carbonate (FEC) and vinylene carbonate (VC), or a combination thereof,  The reactive additive is a compound containing a silyl group, a method for producing an electrolyte additive for a lithium secondary battery:

¾ and R 2 are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, Substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , halogen element (F, CI, Br, or I), or a combination thereof. A is lithium, sodium, or hydrogen.  [Claim 15]  Organic solvents;  First lithium salt; And  Additives;  The additive is an oxidative decomposition type additive containing a compound represented by the following formula (1), a compound represented by the following formula (2), or a mixture thereof,  Electrolytes for Lithium Secondary Batteries: [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,  Xi and ¾ are each, independently of each other, hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or a combination thereof,  n is 1 or 2 and m is 1 or 2.  [Claim 16]  The method of claim 15,  The content of the oxidatively decomposable additive in the electrolyte, which is 0 to 2% by weight, Electrolyte for lithium secondary battery. [Claim 17]  The method of claim 15,  The crab 1 lithium salt is Lithium hexafluoropliosphate (LiPF ₆ ), Lithium tetrafluoroborate (LiBF ₄ ), Lithium perchlorate (LiC10 ₄ ), Lithium hexafluoro arsenate (LiAsF ₆₎ ), Lithium bis (oxalato) borate (LiBOB), lithium bisfluorosulfonylimide (LiFSI) and lithium fluorooxalatoborate (Lithium fluoro (oxalate) borate , LiFOB) at least one selected from  Electrolyte for lithium secondary battery.  [Claim 18]  The method of claim 15,  The concentration of the system 1 lithium salt in the electrolyte,  0.1 to 2 M,  Electrolyte for lithium secondary battery.  [Claim 19]  The method of claim 15,  The organic solvent is  Is an organic solvent that is a carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, aprotic solvent, or a combination thereof,  Electrolyte for lithium secondary battery.  [Claim 20]  The method of claim 15,  The organic solvent,  Ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), or a combination thereof, Electrolyte for lithium secondary battery. [Claim 21]  Preparing a oxidative decomposition type additive by reacting the compound represented by Formula 3 and a boron raw material; And  Comprising mixing the oxidative decomposition type additive with a first lithium salt and an organic solvent to obtain an electrolyte.  Method for preparing an electrolyte for a lithium secondary battery: [Formula 3]

In Chemical Formula 3, ¾ and R 2 are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or 1), or a combination thereof,  A is lithium, sodium, or hydrogen.  [Claim 22]  Organic solvents;  First lithium salt; And  Additives;  The additive includes a reduction decomposition type additive, an oxidative decomposition type additive, and a semi-ung additive; The reduction decomposition additive includes one of fluoroethylene carbonate (FEC) and vinylene carbonate (VC), or a combination thereof, The oxidative decomposition type additive includes a compound represented by the following formula (1), a compound represented by the following formula (2), or a mixture thereof,  The reactive additive is a compound containing a silyl group,  Electrolytes for Lithium Secondary Batteries: [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2  Xi and ¾ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or 1), or a combination thereof, And R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, a substitution Or an unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or their Combination,  n is 1 or 2 and m is 1 or 2.  [Claim 23]  The method of claim 22,  The content of the additive is,  Of the total weight 100% by weight of the electrolyte, 5 to 19% by weight, the electrolyte for a lithium secondary battery.  [Claim 24]  The method of claim 22, The additive total weight 100 parts by weight _^0/0 increases, the reduction decomposable additive containing from 5 to 12 parts by weight _^0/0, the oxidation decomposable additive containing from 0.05 to 2 parts by weight _^0/0, the banung type additive is from 0.1 to It is included in 5% by weight,  Electrolyte for lithium secondary battery.  [Claim 25]  Preparing a oxidative decomposition type additive by reacting the compound represented by Formula 3 and a boron raw material; And  And a step of obtaining an electrolyte by mixing the oxidative decomposition additive, a reduction decomposition additive, a semi-ung additive, a first lithium salt, and an organic solvent, wherein the reduction decomposition additive is fluoroethylene carbonate (fluoroethylene carbonate, FEC) and vinylene carbonate (VC), or combinations thereof,  The semi-finished additive is a compound containing a silyl group,  Method for preparing an electrolyte for a lithium secondary battery: [Formula 3]

In Chemical Formula 3, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or a combination thereof,  A is lithium, sodium, or hydrogen.  [Claim 26]  A positive electrode including a lithium-rich positive electrode active material;  A negative electrode including a silicon-based negative active material; And  An electrolyte comprising an organic solvent, a geylium salt, and an additive; wherein the additive is  It is a compound represented by the following formula (1), a compound represented by the following formula (2), or an oxidative decomposition type additive including a mixture thereof,  Lithium secondary battery: [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2, Xi and X ₂ are each, independently of one another, hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or a combination thereof,  n is 1 or 2 and m is 1 or 2.  [Claim 27]  A positive electrode including a lithium-rich positive electrode active material;  A negative electrode including a negative electrode active material; And  An electrolyte comprising an organic solvent, a first lithium salt, and an additive; wherein the additive includes a reduction decomposition type additive, an oxidative decomposition type additive, and a semi-ung additive;  The reduction decomposition additive includes one of fluoroethylene carbonate (FEC) and vinylene carbonate (VC), or a combination thereof,  The oxidative decomposition type additive includes a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a combination thereof,  The semi-finished additive is a compound containing a silyl group, Lithium secondary battery: [Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,  Xi and ¾ are each, independently of one another, hydrogen, a substituted or unsubstituted C1 to C8 alkoxy group, a halogen element (F, CI, Br, or I), or a combination thereof, ¾ and R ₂ are each independently hydrogen, a substituted or unsubstituted C1 to C8 alkyl group, a substituted or unsubstituted C1 to C8 perfluoro alkyl group, a substituted or unsubstituted C6 to C30 arene group, A substituted or unsubstituted C6 to C30 perfluoro arene group, CF ₃ , a halogen element (F, CI, Br, or I), or a combination thereof,  n is 1 or 2 and m is 1 or 2.  [Claim 28]  The method of claim 26 or 27, The lithium lithium rich cathode active material, To include a compound represented by the formula (5), a lithium secondary battery:  [Formula 5] _{Li x Ni y Mn z Co w} 0 2  In Chemical Formula 5,  1 <χ <2, 0 <≦ 1, 0 <2 ≦ 1, and 0 <\ ^ ≦ 1.  [Claim 29]  The method of claim 26 or 27,  The silicon-based negative active material,  Combination of graphite and silicon, material coated with silicon on the surface of the graphite particles, black is a material coated with silicon and carbon simultaneously on the surface of the graphite particles,  Lithium secondary battery.  [Claim 30]  The method of claim 26 or 27,  The average layer charge voltage of the lithium secondary battery is 4.5 V or more,  Lithium secondary battery.  [Claim 31]  The method of claim 27,  The negative active material is a lithium secondary battery that is a silicon-based negative active material. [Claim 32]  The method of claim 27,  The negative active material is a lithium secondary battery that is a carbon-based negative active material.