TWI744588B - Electrolyte composition and metal-ion battery employing the same - Google Patents

Abstract

An electrolyte composition and a metal-ion battery employing the same are provided. The electrolyte composition includes a metal chloride, an imidazolium salt of Formula (I), an alkali halide, and an oxalate-containing borate

, wherein R¹ , R² , and R³ are independently C_1-8 alkyl, C_2-8 alkenyl、C_2-8 alkynyl, C_1-8 alkoxy, C_2-8 alkoxyalkyl, or C_1-8 fluoroalkyl; and X^- is F^- , Cl^- , Br^- , or I^- . The metal chloride is aluminum chloride, iron chloride, zinc chloride, copper chloride, manganese chloride, chromium chloride, or a combination thereof.

Description

Electrolyte composition and metal ion battery containing the same

This disclosure relates to an electrolyte composition and a metal ion battery containing the electrolyte composition.

Aluminum is abundant in the earth, and electronic devices using aluminum as a material have a lower cost. Because aluminum has low flammability and electronic redox properties, the safety of metal ion batteries in use is greatly improved.

The electrolyte composition used in traditional metal ion batteries contains ionic liquids. Taking aluminum ion batteries as an example, some aluminum ion batteries use aluminum chloride/imidazole chloride salt as the electrolyte composition. Although the traditional electrolyte composition using aluminum chloride/imidazole chloride salt has good electrochemical reversibility, the operating potential of the traditional electrolyte composition is relatively low, which limits the energy density and product use range. In addition, in the conventional electrolyte composition, the molar ratio of aluminum chloride to imidazole chloride salt is not less than 1.3. As a result, the excessive aluminum chloride easily reacts with the water molecules in the environment, causing the electrolyte to decompose, which reduces the cycle stability of the battery, which limits mass production.

Therefore, the industry needs a new electrolyte composition to solve the above-mentioned problems.

式(I) 其中，R¹ , R² , R³ 可獨立為C_1-8 烷基、C_2-8 烯基、C_2-8 炔基、C_1-8 烷氧基、C_2-8 烷氧烷基、或C_1-8 氟烷基；以及，X^- 為F^- , Cl^- , Br^- ,或I^- 。該金屬氯化物為氯化鋁、氯化鐵、氯化鋅、氯化銅、氯化錳、氯化鉻、或上述之組合。According to an embodiment of the present disclosure, the present disclosure provides an electrolyte composition including. The electrolyte composition of the present disclosure includes a metal chloride, an imidazole salt having a structure represented by formula (I), an alkali gold halide, and a borate containing oxalate.

Formula (I) wherein, R ¹ , R ² , and R ³ may independently be C _1-8 alkyl, C _2-8 alkenyl, C _2-8 alkynyl, C _1-8 alkoxy, C _2-8 alkoxyalkyl, or C _1-8 fluoroalkyl group; and, X ^- is ^{F -, Cl -, Br -} , or I ^-. The metal chloride is aluminum chloride, iron chloride, zinc chloride, copper chloride, manganese chloride, chromium chloride, or a combination of the foregoing.

According to an embodiment of the present disclosure, the present disclosure provides a metal ion battery. The metal ion battery may include a positive electrode, a separator, a negative electrode, and the above-mentioned electrolyte composition. Wherein, the negative electrode can be separated from the positive electrode by a separator, and the above-mentioned electrolyte composition can be arranged between the positive electrode and the negative electrode.

The following is a detailed description of the electrolyte composition and the metal ion battery described in this disclosure. It should be understood that the following description provides many different embodiments or examples for implementing different aspects of the present disclosure. The specific elements and arrangements described below are only a brief description of the present disclosure. Of course, these are merely examples and not the limitation of this disclosure. In addition, repeated reference numerals or labels may be used in different embodiments. These repetitions are only to briefly and clearly describe the disclosure, and do not represent any relevance between the different embodiments and/or structures discussed. Moreover, in the drawings, the shape, number, or thickness of the embodiments can be expanded, and are marked for simplicity or convenience. Furthermore, the parts of each element in the drawing will be described separately. It is worth noting that the elements not shown or described in the figure are in the form known to those with ordinary knowledge in the technical field. In addition, the specific The embodiments are only for revealing specific ways of using the present disclosure, and they are not used to limit the present disclosure.

The present disclosure provides an electrolyte composition and a metal ion battery containing the electrolyte composition. According to an embodiment of the present disclosure, the electrolyte composition of the present disclosure includes a metal chloride and is matched with an imidazole salt of a specific structure, and the molar ratio of the metal chloride to the imidazole salt is controlled within a specific range. In addition to metal chlorides and imidazole salts, the electrolyte composition of the present disclosure also contains a specific content of alkali gold halide and a specific content of oxalate-containing borate. In this way, the electrolyte composition of the present disclosure has high conductivity, stability, and redox reactivity, which can increase the operating potential (median voltage of not less than 3.0V) and energy of the metal ion battery containing the electrolyte composition. Density, cycle stability, and extend the cycle life of metal ion batteries.

式(I) 其中，R¹ , R² , R³ 可獨立為C_1-8 烷基、C_2-8 烯基、C_2-8 炔基、C_1-8 烷氧基、C_2-8 烷氧烷基、或C_1-8 氟烷基；以及，X^- 為F^- , Cl^- , Br^- ,或I^- 。According to an embodiment of the present disclosure, the electrolyte composition of the present disclosure includes a metal chloride, an imidazole salt having a structure represented by formula (I), an alkali gold halide, and a borate containing oxalate,

Formula (I) wherein, R ¹ , R ² , and R ³ may independently be C _1-8 alkyl, C _2-8 alkenyl, C _2-8 alkynyl, C _1-8 alkoxy, C _2-8 alkoxyalkyl, or C _1-8 fluoroalkyl group; and, X ^- is ^{F -, Cl -, Br -} , or I ^-.

According to an embodiment of the present disclosure, the metal chloride may be aluminum chloride, ferric chloride, zinc chloride, copper chloride, manganese chloride, chromium chloride, or a combination thereof. Here, the metal chlorides mentioned in the present disclosure may be chlorides with metals with different positive valence numbers. For example, the aluminum chloride described in the present disclosure may be AlCl ₂ , AlCl ₃ , or a combination thereof; copper chloride may be CuCl, CuCl ₂ , or a combination thereof; iron chloride may be FeCl ₂ , FeCl ₃ , or The combination; chromium chloride can be CrCl ₂ , CrCl ₃ , or a combination thereof; zinc chloride can be ZnCl ₂ , ZnCl ₄ , or a combination thereof; and manganese chloride can be MnCl ₂ , MnCl ₃ , or a combination thereof.

According to an embodiment of the present disclosure, the C _1-8 alkyl group may be a linear or branched chain alkyl group. For example, C _1-8 alkyl can be methyl, ethyl, propyl, butyl, pentyl, hexyl, heptenyl (heptyl), octyl (octyl), or isomers thereof. According to an embodiment of the present disclosure, the C _2-8 alkenyl group may be a linear or branched alkenyl group. For example, the C _2-8 alkenyl group can be ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl ), octenyl, or isomers thereof. According to an embodiment of the present disclosure, the C _2-8 alkynyl group may be a linear or branched alkynyl group. For example, C _2-8 alkynyl group can be ethynyl (ethynyl), propynyl (propynyl), butynyl (butynyl), pentynyl (pentynyl), hexynyl (hexynyl), heptynyl ( heptynyl), octynyl, or isomers thereof. According to an embodiment of the present disclosure, the C _1-8 alkoxy group may be a linear or branched chain alkoxy group. For example, the C _1-8 alkoxy group can be methoxy, ethoxy, propoxy, butoxy, pentoxy, and hexoxy. Hexoxy, heptoxy, octoxy, or isomers thereof. According to an embodiment of the present disclosure, the C _2-8 alkoxyalkyl group may be a linear or branched alkoxyalkyl group. The C _2-8 alkoxyalkyl group can be methoxymethyl, ethoxymethyl, methoxyethyl, propoxymethyl, or isomers thereof . According to the embodiment of the present disclosure, C _1-8 fluoroalkyl refers to an alkyl in which all or part of the hydrogen on the carbon is replaced by fluorine, and can be linear or branched, such as fluoromethyl, Fluoroethyl, fluoropropyl, or isomers thereof. Here, the fluoromethyl group in the present disclosure can be monofluoromethyl, difluoromethyl, or perfluoromethyl, and the fluoroethyl group can be monofluoroethyl, difluoroethyl, trifluoroethyl, or tetrafluoroethyl. Fluoroethyl, or perfluoroethyl.

According to the embodiment of the present disclosure, R ¹ , R ² , and R ³ may independently be methyl, ethyl, propyl, butyl, pentyl, hexyl ), heptyl, octyl, or isomers thereof. According to an embodiment of the present disclosure, the C _2-8 alkenyl group may be a linear or branched alkenyl group. For example, the C _2-8 alkenyl group can be ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl ), octenyl (octenyl), vinyl (ethenyl), propenyl (propenyl), butenyl (butenyl), pentenyl (pentenyl), hexenyl (hexenyl), heptenyl (heptenyl), oct Alkenyl (octenyl), ethynyl (ethynyl), propynyl (propynyl), butynyl (butynyl), pentynyl (pentynyl), hexynyl (hexynyl), heptynyl (heptynyl), octynyl (octynyl), methoxymethyl, ethoxymethyl, methoxyethyl, propoxymethyl, fluoromethyl, fluoroethyl, or fluoropropyl.

，其中R¹ 與X的定義如上述。舉例來說，本揭露所述咪唑鹽可為1,2-二甲基-3-丙基咪唑氯鹽(1,2-dimethyl-3-propylimidazolium chloride、DMPIC)、1,2-二甲基-3-丙基咪唑碘鹽(1,2-dimethyl-3-propylimidazolium iodide)、1,2-二甲基-3-丙基咪唑溴鹽(1,2-dimethyl-3-propylimidazolium bromide)、1,2-二甲基-3-丙基咪唑氟鹽(1,2-dimethyl-3-propylimidazolium fluoride)、1,2-二甲基-3-丁基咪唑氯鹽(1,2-dimethyl-3-butylimidazolium chloride、DMBIC)、1,2-二甲基-3-丁基咪唑碘鹽(1,2-dimethyl-3-butylimidazolium iodide)、1,2-二甲基-3-丁基咪唑溴鹽(1,2-dimethyl-3-butylimidazolium bromide)、1,2-二甲基-3-丁基咪唑氟鹽(1,2-dimethyl-3-butylimidazolium fluoride)、1,2-二甲基-3-乙基咪唑氯鹽(1,2-dimethyl-3-ethylimidazolium chloride、DMEIC)、1,2-二甲基-3-乙基咪唑碘鹽(1,2-dimethyl-3-ethylimidazolium iodide)、1,2-二甲基-3-乙基咪唑溴鹽(1,2-dimethyl-3-ethylimidazolium bromide)、1,2-二甲基-3-乙基咪唑氟鹽(1,2-dimethyl-3-ethylimidazolium fluoride)、或上述之組合。According to the embodiment of the present disclosure, the imidazole salt having the structure represented by formula (I) of the present disclosure may be

, Where R ¹ and X are as defined above. For example, the imidazole salt in the present disclosure can be 1,2-dimethyl-3-propylimidazolium chloride (DMPIC), 1,2-dimethyl- 3-propylimidazolium iodide (1,2-dimethyl-3-propylimidazolium iodide), 1,2-dimethyl-3-propylimidazolium bromide (1,2-dimethyl-3-propylimidazolium bromide), 1, 2-dimethyl-3-propylimidazolium fluoride (1,2-dimethyl-3-propylimidazolium fluoride), 1,2-dimethyl-3-butylimidazolium fluoride (1,2-dimethyl-3- butylimidazolium chloride, DMBIC), 1,2-dimethyl-3-butylimidazolium iodide (1,2-dimethyl-3-butylimidazolium iodide), 1,2-dimethyl-3-butylimidazolium bromide ( 1,2-dimethyl-3-butylimidazolium bromide), 1,2-dimethyl-3-butylimidazolium fluoride (1,2-dimethyl-3-butylimidazolium fluoride), 1,2-dimethyl-3- Ethyl imidazole chloride (1,2-dimethyl-3-ethylimidazolium chloride, DMEIC), 1,2-dimethyl-3-ethylimidazolium iodide (1,2-dimethyl-3-ethylimidazolium iodide), 1, 2-dimethyl-3-ethylimidazolium bromide (1,2-dimethyl-3-ethylimidazolium bromide), 1,2-dimethyl-3-ethylimidazolium bromide (1,2-dimethyl-3- ethylimidazolium fluoride), or a combination of the above.

According to the embodiments of the present disclosure, the electrolyte composition of the present disclosure does not include other imidazole salts and ionic liquids except for the imidazole salt having the structure represented by formula (I), so as to avoid the conductivity, stability, and conductivity of the electrolyte composition. The redox reactivity is reduced by the influence of other imidazole salts and ionic liquids.

Here, when other imidazole salts (such as 1-butyl-3-methylimidazole chloride (BMIC) or 1-ethyl-3-methylimidazole chloride (EMIC)) are substituted for the electrolyte composition of the present disclosure When the imidazole salt with the structure represented by formula (I) is used, it will be observed that the metal ion battery containing the electrolyte composition has a longer low potential platform and a shorter high potential platform during the discharge process, resulting in metal The operating potential of the ion battery decreases. For example, replace 1-butyl-3-methylimidazole chloride with 1-butyl-3-methylimidazole chloride (BMIC) or 1-ethyl-3-methylimidazole chloride (EMIC) ( BMIC) or 1-ethyl-3-methylimidazole chloride (EMIC), the resulting metal ion battery discharge median voltage will be less than 2.5V.

According to an embodiment of the present disclosure, in the electrolyte composition of the present disclosure, the molar ratio of the metal chloride to the imidazole salt is 1.05 to 1.2, such as 1.08, 1.1, 1.12, 1.15, or 1.18. If the molar ratio of the metal chloride to the imidazole salt is too low, the resulting electrolyte composition will be Lewis alkaline, and the alkali-gold halide will be less likely to be completely dissolved in the electrolyte composition to form a eutectic, resulting in the electrolyte composition The conductivity, stability, and redox reactivity are reduced; and if the molar ratio of the metal chloride to the imidazole salt is too high, the resulting electrolyte composition will be Lewis acidic, resulting in conductivity and stability of the electrolyte composition , Redox reactivity is reduced, and the potential window cannot be enlarged.

According to the embodiment of the present disclosure, the alkali gold halide of the present disclosure may be lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, lithium fluoride, sodium fluoride, potassium fluoride, and fluorine. Rubidium, cesium fluoride, lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, lithium iodide, sodium iodide, potassium iodide, rubidium iodide, cesium iodide, or a combination of the above.

According to an embodiment of the present disclosure, the ratio of the weight of the alkali gold halide to the total weight of the metal chloride and the imidazole salt may be 1:100 to 6:100, such as 2:100 to 6:100, or 2.5:100 , 3:100, 4:100, 5:100, or 5.5:100. If the ratio of the weight of the alkali gold halide to the total weight of the metal chloride and imidazole salt is too low, the resulting electrolyte composition will be Lewis acidic, and the electrolyte composition will easily form Al ₂ C ₇ ^{-during charge and discharge.} , It is easy to form an aluminum-plated layer on the negative electrode, resulting in the reduction of the operating potential, energy density, cycle stability, and cycle life of the metal ion battery; and, if the weight of the alkali gold halide and the total weight of the metal chloride and imidazole salt If the ratio is too high, the alkali gold halide cannot be completely dissolved in the electrolyte composition to form a eutectic, resulting in a decrease in the conductivity, stability, and redox reactivity of the electrolyte composition.

，其中R⁴ 及R⁵ 係鹵素(例如氟、氯、溴、或碘)；以及，M⁺ 係Li⁺ 或Na⁺ 。此外， R⁴ 及R⁵ 亦可構成一草酸根(

)，因此揭露所述含草酸根的硼酸鹽可為

，其中M⁺ 係Li⁺ 或Na⁺ 。According to the embodiment of the present disclosure, the oxalate-containing borate of the present disclosure may be

, Wherein R ⁴ and R ⁵ are halogen (for example, fluorine, chlorine, bromine, or iodine); and, M ⁺ is Li ⁺ or Na ⁺ . In addition, R ⁴ and R ⁵ can also form an oxalate (

), so it is revealed that the oxalate-containing borate can be

, Where M ⁺ is Li ⁺ or Na ⁺ .

According to the disclosed embodiment, the oxalate-containing borate is lithium bis(oxalato)borate (LiBOB), sodium bis(oxalato)borate (NaBOB), lithium difluorooxalatoborate (lithium bis(oxalato) borate, NaBOB), and lithium bis(oxalato) borate (LiBOB). difluoro (oxalato) borate (LiODFB), sodium difluoro (oxalato) borate (NaODFB), or a combination of the above. Since the electrolyte composition of the present disclosure contains the oxalate-containing borate (for example, lithium dioxalate borate or lithium difluorooxalate borate), the metal ion battery containing the electrolyte composition can form non-oxidizing materials during charging and discharging. The mesh (or dendritic) membrane layer that will be dissolved by the ionic liquid (ie, the imidazole salt described in this disclosure) increases the cycle stability and cycle life of the metal ion battery. When using other alkali gold salts (for example: LiPF ₆ , LiBF ₄ , LiClO ₄ , LiCF ₃ SO ₃ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiFSI (double (fluorine) Lithium sulfonyl) amide, lithium bis (fluorosulfonyl) imide), or LiTFSI (bis(trifluoromethylsulfonyl) imide), lithium bis(trifluoromethylsulfonyl) imide), carbonate (for example: ethylene carbonate (ethylene carbonate) carbonate, EC), vinylene carbonate (VC), fluoroethylene carbonate (FEC)), or sulfur-containing compounds (ES; ethylene sulfite), or benzenesulfonate When benzenesulfonyl chloride (benzenesulfonyl chloride) replaces the oxalate-containing borate described in this disclosure, the film formed by the alkali metal salts, carbonates, or sulfur-containing compounds during the charging and discharging process of the metal ion battery Will be dissolved by the ionic liquid, so the oxalate-containing borate cannot form a network (or dendritic) film that cannot be dissolved by the ionic liquid during the charging and discharging process of the battery, and cannot improve the cycle stability of the metal ion battery. Performance, and cycle life.

According to an embodiment of the present disclosure, the ratio of the molar number of the oxalate-containing borate to the total molar number of the metal chloride and imidazole salt is 0.1:100 to 2:100, for example, 0.1:100 to 1.8: 100, another example is 0.2:100, 0.5:100, 0.8:100, 1:100, 1.2:100, 1.5:100, or 1.75:100. If the ratio of the molar number of the oxalate-containing borate to the total molar number of the metal chloride and imidazole salt is too low, the oxalate-containing borate with too little content cannot be formed during the charging and discharging process of the metal ion battery Net-like (or dendritic) film layer, so it is impossible to further improve the cycle stability and cycle life of metal ion batteries; and, if the moles of oxalate-containing borate and the total moles of metal chlorides and imidazole salts If the ratio of the numbers is too high, the power loss of the metal ion battery will increase and the energy density of the metal ion battery will decrease.

According to the embodiment of the present disclosure, the electrolyte composition of the present disclosure may be composed of the above-mentioned metal chloride, the imidazole salt having the structure represented by formula (I), the above-mentioned alkali gold halide, and the above-mentioned oxalate-containing borate.

According to the embodiment of the present disclosure, the present disclosure also provides a metal ion battery. Please refer to FIG. 1, which is a schematic diagram of the metal ion battery 100 according to an embodiment of the disclosure. The metal ion battery 100 can include a positive electrode 10, a negative electrode 12, and a separator 14, wherein the separator 14 can be disposed between the positive electrode 10 and the negative electrode 12, so that the negative electrode is separated from the separator 14 and the positive electrode. Be separated to avoid direct contact between the positive electrode 10 and the negative electrode 12. The metal ion battery 100 includes the above-mentioned electrolyte composition 20 disposed in the metal ion battery 100 and located between the positive electrode and the negative electrode, so that the electrolyte composition 20 is in contact with the positive electrode 10 and the negative electrode 12. The metal ion battery 100 may be a rechargeable secondary battery, but this disclosure also covers a primary battery.

According to an embodiment of the present disclosure, the positive electrode 10 may include a positive electrode collector layer and a positive electrode active material disposed on the positive electrode collector layer. According to an embodiment of the present disclosure, the positive electrode can also be composed of the positive electrode collector layer and the positive electrode active material. According to an embodiment of the present disclosure, the positive electrode current collector layer may be a conductive carbon substrate, such as carbon cloth, carbon felt, or carbon paper. For example, the conductive carbon substrate may have a sheet resistance between about 1 mW×cm ² to 6 mW×cm ² and a carbon content greater than about 65 wt %. According to an embodiment of the present disclosure, the positive collector layer may be a metal material with a porous structure, such as a 3D mesh structure metal material (such as nickel mesh, copper mesh, or molybdenum mesh) or a foamed structure metal material (such as foamed nickel). , Foamed copper, or foamed molybdenum). According to an embodiment of the present disclosure, a metal material with a porous structure may have a porosity P of about 50% to 80% (for example, about 60%, or 70%), and the porosity P can be determined by the following formula: P=V1/ V2´100%, where V1 is the volume occupied by the pores in the positive collector layer, and V2 is the overall volume of the positive collector layer. According to an embodiment of the present disclosure, the current collecting layer may be a composite layer of a conductive carbon substrate and a metal material.

According to an embodiment of the present disclosure, the positive electrode active material can be a carbon material with a layered structure, layered double hydroxide, layered oxide, layered chalcogenide, vanadium-based oxide Compounds, or metal sulfides, or agglomerates of the above materials. According to an embodiment of the present disclosure, the carbon material with a layered structure can be graphite, carbon nanotube, graphene, or a combination of the foregoing. According to an embodiment of the present disclosure, the carbon material with a layered structure can be an intercalated carbon material, such as graphite (including natural graphite, artificial graphite, pyrolytic graphite, foamed graphite, flake graphite, or expanded graphite), graphene , Carbon nanotubes or a combination of the above materials. According to an embodiment of the present disclosure, the positive electrode active material can be directly grown (for example, the positive electrode active material is formed by chemical vapor deposition (CVD)) on the positive electrode collector layer (that is, there is no dielectric between the two). ), or using adhesives (for example: polyvinyl alcohol, polytetrafluoroethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride, polystyrene butadiene copolymer, fluorinated rubber, polyurethane, polyethylene Base pyrrolidone, polyethyl acrylate, polyvinyl chloride, polyacrylonitrile, polybutadiene, polyacrylic acid, or a combination of the above) the positive electrode active material is fixed on the positive electrode collector layer. According to an embodiment of the present disclosure, when the positive electrode collector layer is a porous structured metal material, the positive electrode active material can be further filled into the holes of the metal material.

According to the disclosed embodiment, the material of the isolation film 14 can be glass fiber, polyethylene (PE), polypropylene (Polypropylene, PP), non-woven fabric, wood fiber, poly (ether sulfones), PES ), ceramic fiber, etc. or a combination of the above.

According to an embodiment of the present disclosure, the negative electrode 12 includes a negative electrode active material, wherein the negative electrode active material can be a metal (for example) or an alloy of the metal, a carbon material with a layered structure, a layered double hydroxide (layered double hydroxide) hydroxide), layered oxide, layered chalcogenide, vanadium-based oxide, metal sulfide, or agglomerates of the above materials. According to an embodiment of the present disclosure, the metal may be aluminum, copper, iron, indium, nickel, tin, chromium, yttrium, titanium, manganese, or molybdenum. According to an embodiment of the present disclosure, the carbon material with a layered structure can be graphite, carbon nanotube, graphene, or a combination of the foregoing. According to an embodiment of the present disclosure, the carbon material with a layered structure can be an intercalated carbon material, such as graphite (including natural graphite, artificial graphite, pyrolytic graphite, foamed graphite, flake graphite, or expanded graphite), graphene , Carbon nanotubes or a combination of the above materials. According to the disclosed embodiment, the negative electrode 12 may further include a negative electrode collector layer, and the negative electrode active material can be directly grown (for example, the positive electrode active material is formed by a chemical vapor deposition method) on the negative electrode collector layer (that is, both Without any medium between them), or use adhesives (for example: polyvinyl alcohol, polytetrafluoroethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride, polystyrene butadiene copolymer, fluorinated rubber, poly Urethane, polyvinylpyrrolidone, polyethyl acrylate, polyvinyl chloride, polyacrylonitrile, polybutadiene, polyacrylic acid, or a combination of the above) fix the negative electrode active material on the negative electrode collector layer. According to an embodiment of the present disclosure, the negative electrode current collector layer may be a conductive carbon substrate, such as carbon cloth, carbon felt, or carbon paper. For example, the conductive carbon substrate may have a sheet resistance between about 1 mW×cm ² to 6 mW×cm ² and a carbon content greater than about 65 wt %. According to an embodiment of the present disclosure, the negative electrode current collector layer may be a metal material with a porous structure, such as a 3D mesh structure metal material (such as nickel mesh, copper mesh, or molybdenum mesh) or a foamed structure metal material (such as foamed nickel). , Foamed copper, or foamed molybdenum). According to an embodiment of the present disclosure, a metal material with a porous structure may have a porosity P of about 50% to 80% (for example, about 60%, or 70%), and the porosity P can be determined by the following formula: P=V1/ V2´100%, where V1 is the volume occupied by the pores in the negative electrode collector layer, and V2 is the overall volume of the negative electrode collector layer. According to an embodiment of the present disclosure, the negative electrode current collector layer may be a composite layer of a conductive carbon substrate and a metal material. According to an embodiment of the present disclosure, when the negative electrode current collector layer is a porous structured metal material, the negative electrode active material can be further filled into the holes of the metal material. According to an embodiment of the present disclosure, the negative electrode can also be composed of the negative electrode collector layer and the negative electrode active material. According to the disclosed embodiment, the material and structure of the positive electrode 10 and the negative electrode 12 are the same.

In order to make the above and other objectives, features, and advantages of the present disclosure more obvious and understandable, the following specific examples with accompanying drawings are described in detail as follows:

Preparation Example 1 of the electrolyte composition aluminum chloride and 1,2-dimethyl-3-propylimidazolium chloride (1,2-dimethyl-3-propylimidazolium chloride, DMPIC) were mixed, wherein the aluminum chloride was mixed with The molar ratio of 1,2-dimethyl-3-propylimidazole chloride (DMPIC) is 1.1. Then, lithium chloride is added, wherein the weight percentage of lithium chloride is 5.2% by weight, based on the total weight of aluminum chloride and 1,2-dimethyl-3-propylimidazole chloride salt. After stirring for 12 hours, lithium bis(oxalato)borate (LiBOB) was added. The molar percentage of lithium bis(oxalato)borate was 1 mol%, and aluminum chloride and 1,2-dimethyl-3- The total number of moles of propylimidazole chloride is the basis. After continuing the stirring for 12 hours, an electrolyte composition (1) was obtained.

Example 2 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that the molar percentage of lithium dioxalate borate was reduced from 1 mol% to 0.5 mol% to obtain the electrolyte composition (2).

Example 3 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that the molar percentage of lithium dioxalate borate was increased from 1 mol% to 1.5 mol% to obtain the electrolyte composition (3).

Example 4 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that the mole percentage of lithium dioxalate borate was increased from 1 mol% to 2.0 mol% to obtain the electrolyte composition (4).

Comparative Example 1 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that the molar ratio of aluminum chloride to 1,2-dimethyl-3-propylimidazolium chloride (DMPIC) was determined by 1.1 was reduced to 0.95 to obtain electrolyte composition (5).

Comparative Example 2 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that the molar ratio of aluminum chloride to 1,2-dimethyl-3-propylimidazolium chloride (DMPIC) was determined by 1.1 was reduced to 1, and electrolyte composition (6) was obtained.

Comparative Example 3 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that lithium dioxalate borate (LiBOB) was not added to obtain the electrolyte composition (7).

Comparative Example 4 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that 1,2-dimethyl-3-propylimidazole chloride salt (DMPIC) was used as 1-ethyl-3-methyl Imidazole chloride salt (1-ethyl-3-methylimidazolium chloride, EMIC) was substituted to obtain electrolyte composition (8).

Comparative Example 5 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that 1,2-dimethyl-3-propylimidazole chloride salt (DMPIC) was used as 1-butyl-3-methyl Imidazole chloride salt (1-butyl-3-methylimidazolium chloride, BMIC) was substituted to obtain electrolyte composition (9).

Comparative Example 6 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that no lithium chloride was added, and the electrolyte composition (10) was obtained.

Comparative Example 7 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that vinyl sulfite (ES) was substituted for lithium dioxalate borate (LiBOB) to obtain electrolyte composition (11).

Comparative Example 8 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that 2-fluoroethylene carbonate (FEC) was substituted for lithium dioxalate borate (LiBOB) to obtain electrolyte composition (12).

Example 5 The preparation method of the electrolyte composition (1) described in Example 1 was carried out, except that the weight percentage of lithium chloride was reduced from 5.2% by weight to 1.3% by weight, to obtain an electrolyte composition (13).

Metal ion battery Example 6 First, provide a nickel foam board (size 100mm x 100mm, thickness 0.2mm, porosity 90%, and pore diameter 200μm). Then, the nickel foamed plate was placed in a vacuum high-temperature furnace, and hydrogen and argon gas (as transport gas) were introduced, and methane was simultaneously introduced for graphite vapor deposition (temperature between 900 and 1100 ℃), to obtain The nickel foam board (the graphite loading amount is 800-1500mg) coated with a graphite layer on the surface is used as a graphite electrode. Next, provide an isolation film (glass filter paper (6 layers 1/2 inch), product code: Whatman 934-AH). Next, the graphite electrode (as a negative electrode), a separator, and a graphite electrode (as a positive electrode) are arranged in this order, and they are packaged with an aluminum plastic film and injected into the electrolyte composition (1) to obtain a metal ion battery (1).

Then, after activating the metal ion battery (1) with a current of 80 mA/g, perform a charge-discharge cycle test on the metal ion battery (1) with a current of 500 mA/g (charge to 4.2v), and measure the metal ion battery (1) The discharge median voltage and energy density at the 9th cycle, and the cycle life (15th cycle discharge energy density/maximum energy density x 100%). The results are shown in Table 1.

Example 7-9 The preparation method of the metal ion battery (1) described in Example 6 was carried out, except that the electrolyte composition (1) was replaced by the electrolyte composition (2)-(4), respectively, to obtain a metal ion battery (2) -(4).

Next, measure the median discharge voltage and energy density and cycle life of the metal ion batteries (2)-(4) at the 9th cycle in the above-mentioned manner (discharge energy density at the 15th cycle/maximum energy density x 100%) , The results are shown in Table 1.

Comparative Examples 9-16 The preparation method of the metal ion battery (1) described in Example 6 was carried out, except that the electrolyte composition (1) was replaced by the electrolyte composition (5)-(12), respectively, to obtain a metal ion battery (5) -(12).

Next, measure the median discharge voltage and energy density and cycle life of the metal ion batteries (5)-(12) at the 9th cycle in the above-mentioned manner (discharge energy density at the 15th cycle/maximum energy density x 100%) , The results are shown in Table 1.

Example 10 The preparation method of the metal ion battery (1) described in Example 6 was performed, except that the electrolyte composition (13) was used instead of the electrolyte composition (1) to obtain a metal ion battery (13).

Next, measure the median discharge voltage and energy density of the metal ion battery (13) at the 9th cycle and the cycle life (discharge energy density at the 15th cycle/maximum energy density x 100%) of the metal ion battery (13) in the above-mentioned manner. The results are shown in the table 1 shown.

Table 1

It can be seen from Table 1 that the molar ratio of the metal chloride and imidazole salt of the electrolyte composition used in Comparative Example 9 and Comparative Example 10 is less than 1.05:1, even though the electrolyte composition used in Comparative Example 9 and Comparative Example 10 Adding the alkali gold halide and oxalate-containing borate described in the present disclosure, the operating potential (less than 3.1V) and cycle life (less than 70%) of the resulting metal ion battery are significantly better than those described in Examples 6-10 The metal ion battery is poor. Since the electrolyte composition used in Comparative Example 11 did not add the oxalate-containing borate described in this disclosure, the energy density (less than 160mWh/g) of the resulting metal ion battery was significantly worse than that of the metal ion battery described in Examples 6-8 . Since Comparative Example 12 and Comparative Example 13 use EMIC and BMIC to replace the imidazole salt with the structure of formula (I) described in this disclosure, the operating potential (less than 2.1V) of the resulting metal ion battery is significantly higher than that of Examples 6-10. The metal ion battery described is poor. In addition, since the electrolyte composition used in Comparative Example 14 did not add the alkali-gold halide described in this disclosure, the operating potential of the resulting metal ion battery (less than 2.3V) was significantly higher than that of the metal ion battery described in Examples 6-10. Difference. Furthermore, since Comparative Example 15 and Comparative Example 16 replaced the oxalate-containing borate described in this disclosure with ES and FEC respectively, the energy density (less than 105 mWh/g) of the resulting metal ion battery was significantly higher than that described in Examples 6-8. The energy density (greater than 163mWh/g) of the metal ion battery is poor.

Although this disclosure has been disclosed in several embodiments as above, it is not intended to limit this disclosure. Anyone with ordinary knowledge in the art can make any changes and modifications without departing from the spirit and scope of this disclosure. Therefore, the protection scope of this disclosure shall be subject to those defined by the attached patent application scope.

10: positive electrode 12: negative electrode 14: separator 20: electrolyte composition 100: metal ion battery

FIG. 1 is a schematic diagram of the metal ion battery according to an embodiment of the disclosure.

10: positive

12: negative electrode

14: Isolation film

20: Electrolyte composition

100: Metal ion battery

Claims (17)

An electrolyte composition comprising: a metal chloride, wherein the metal chloride is aluminum chloride, ferric chloride, zinc chloride, copper chloride, manganese chloride, chromium chloride, or a combination thereof; an imidazole salt , Has the structure shown in formula (I)

, Where R ¹ , R ² , and R ³ are independently C _1-8 alkyl, C _2-8 alkenyl, C _2-8 alkynyl, C _1-8 alkoxy, C _2-8 alkoxyalkyl , or a C _1-8 fluoroalkyl group; and, X ^- is ^{F -, Cl -, Br -} , or I ^-; an alkali metal halides; and perborate-containing oxalate (oxalato-containing borate), The molar ratio of the metal chloride to the imidazole salt is 1.05 to 1.2; the ratio of the weight of the alkali gold halide to the total weight of the metal chloride and the imidazole salt is 1:100 to 6:100; and The ratio of the molar number of the oxalate-containing borate to the total molar number of the metal chloride and imidazole salt is 0.1:100 to 2:100. The electrolyte composition described in item 1 of the scope of patent application, wherein the imidazole salt is

, Where R ¹ is C _1-8 alkyl, C _2-8 alkenyl, C _2-8 alkynyl, C _1-8 alkoxy, C _2-8 alkoxyalkyl, or C _1-8 fluoroalkane group; and, X ^- is ^{F -, Cl -, Br -} , or I ^-. The electrolyte composition described in item 2 of the scope of patent application, wherein the imidazole salt is 1,2-dimethyl-3-propylimidazolium chloride (DMPIC), 1 ,2-Dimethyl-3-propylimidazolium iodide (1,2-dimethyl-3-propylimidazolium iodide), 1,2-dimethyl-3-propylimidazolium iodide (1,2-dimethyl-3 -propylimidazolium bromide), 1,2-dimethyl-3-propylimidazolium fluoride (1,2-dimethyl-3-propylimidazolium fluoride), 1,2-dimethyl-3-butylimidazolium chloride (1 ,2-dimethyl-3-butylimidazolium chloride, DMBIC), 1,2-dimethyl-3-butylimidazolium iodide, 1,2-dimethyl-3 -Butylimidazole bromide (1,2-dimethyl-3-butylimidazolium bromide), 1,2-dimethyl-3-butylimidazolium fluoride (1,2-dimethyl-3-butylimidazolium fluoride), 1,2 -Dimethyl-3-ethylimidazolium chloride (1,2-dimethyl-3-ethylimidazolium chloride, DMEIC), 1,2-dimethyl-3-ethylimidazolium chloride (1,2-dimethyl-3 -ethylimidazolium iodide), 1,2-dimethyl-3-ethylimidazolium bromide, 1,2-dimethyl-3-ethylimidazolium bromide (1 ,2-dimethyl-3-ethylimidazolium fluoride), or a combination of the above. The electrolyte composition described in item 1 of the scope of patent application, wherein the alkali gold halide is lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, fluoride Lithium, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, lithium iodide, sodium iodide, potassium iodide, rubidium iodide, Cesium iodide, or a combination of the above. The electrolyte composition described in item 1 of the scope of patent application, wherein the oxalate-containing borate is

, Where R ⁴ and R ⁵ are halogen, or R ⁴ and R ⁵ constitute an oxalate (

); And, M ⁺ is Li ⁺ or Na ⁺ . The electrolyte composition described in item 1 of the scope of patent application, wherein the oxalato-containing borate is lithium bis(oxalato)borate (LiBOB), sodium bis(oxalato)borate, NaBOB), lithium difluoro (oxalato) borate (LiODFB), sodium difluoro (oxalato) borate (NaODFB), or a combination of the above. A metal ion battery, comprising: a positive electrode; a separator; a negative electrode, wherein the negative electrode is separated from the positive electrode by a separator; Between the positive electrode and the negative electrode. According to the metal ion battery described in item 7 of the scope of patent application, the positive electrode is composed of a positive electrode current collector layer and a positive electrode active material. The metal ion battery described in item 8 of the scope of patent application, wherein the positive electrode collector layer is a conductive carbon substrate, a metal material with a porous structure, or a combination of the foregoing. The metal ion battery described in item 8 of the scope of patent application, wherein the positive electrode active material is a carbon material with a layered structure, a layered double hydroxide, a layered oxide, and a layered chalcogenide (layered chalcogenide), vanadium-based oxide, or metal sulfide. For the metal ion battery described in item 10 of the scope of patent application, the carbon material with a layered structure is natural graphite, artificial graphite, pyrolytic graphite, foamed graphite, flake graphite, expanded graphite, graphene, carbon nanotubes , Or a combination of the above materials. According to the metal ion battery described in item 7 of the scope of patent application, the negative electrode includes a negative electrode active material. The metal ion battery described in item 12 of the scope of patent application, wherein the negative electrode active material is a metal or an alloy of the metal, a carbon material with a layered structure, a layered double hydroxide, a layered Oxide, layered chalcogenide, vanadium-based oxide, or metal sulfide. The metal ion battery described in item 13 of the scope of patent application, wherein the metal is copper, iron, aluminum, zinc, indium, nickel, tin, chromium, yttrium, titanium, manganese, or molybdenum. The metal ion battery described in item 13 of the scope of patent application, wherein the carbon material with a layered structure is natural graphite, artificial graphite, pyrolytic graphite, foamed graphite, and flakes Graphite, expanded graphite, graphene, carbon nanotubes, or a combination of the above materials. The metal ion battery according to item 12 of the scope of patent application, wherein the negative electrode further comprises a negative electrode current collector layer, the negative electrode current collector layer is a conductive carbon substrate, nickel mesh, foamed nickel, molybdenum mesh, foamed molybdenum , Or a combination of the above. For the metal ion battery described in item 7 of the scope of patent application, the isolation film is made of glass fiber, polyethylene (PE), polypropylene (Polypropylene, PP), non-woven fabric, wood fiber, polyether resin (Poly(ether) sulfones), PES), ceramic fiber, or a combination of the above.

Images