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WO2016167591A1 - Matériau actif d'électrode négative et procédé permettant de préparer ce dernier - Google Patents

Matériau actif d'électrode négative et procédé permettant de préparer ce dernier Download PDF

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Publication number
WO2016167591A1
WO2016167591A1 PCT/KR2016/003926 KR2016003926W WO2016167591A1 WO 2016167591 A1 WO2016167591 A1 WO 2016167591A1 KR 2016003926 W KR2016003926 W KR 2016003926W WO 2016167591 A1 WO2016167591 A1 WO 2016167591A1
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Prior art keywords
negative electrode
active material
artificial graphite
electrode active
oxygen
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English (en)
Korean (ko)
Inventor
김현욱
김은경
신선영
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LG Chem Ltd
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LG Chem Ltd
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Priority claimed from KR1020160045345A external-priority patent/KR101913902B1/ko
Application filed by LG Chem Ltd filed Critical LG Chem Ltd
Priority to US15/558,631 priority Critical patent/US11152621B2/en
Publication of WO2016167591A1 publication Critical patent/WO2016167591A1/fr
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a negative electrode active material and a method of manufacturing the same.
  • a representative example of an electrochemical device using such electrochemical energy is a secondary battery, and its use area is gradually increasing.
  • portable devices such as portable computers, portable telephones, cameras, and the like
  • secondary batteries exhibit high energy density and operating potential, and have a cycle life.
  • Many studies have been conducted on this long, low self-discharge rate lithium battery and are commercially available and widely used.
  • a typical lithium secondary battery uses graphite as a negative electrode active material, and charging and discharging are performed while repeating a process in which lithium ions of a positive electrode are inserted into and detached from a negative electrode.
  • the theoretical capacity of the battery is different depending on the type of the electrode active material, but as the cycle progresses, the charge and discharge capacity is generally lowered.
  • This phenomenon is most likely due to the separation between the electrode active material or between the electrode active material and the current collector due to the volume change of the electrode generated as the charge and discharge of the battery progresses, the active material does not perform its function.
  • the negative electrode for a nonaqueous secondary battery comprising graphite, carbon black, and an aqueous binder
  • the carbon black includes particles having an aspect ratio of 1.0 or more and 5.0 or less and a maximum diameter of 0.05 ⁇ m or more and 10 ⁇ m or less.
  • a negative electrode for a nonaqueous secondary battery characterized in that the electrode density of the negative electrode is 1.50 g / cm 3 to 1.80 g / cm 3, wherein graphite is disclosed that artificial graphite can be preferably used.
  • the first technical problem to be solved of the present invention is to provide a negative electrode active material that can improve the dispersibility in the aqueous system by modifying the surface of the artificial graphite to hydrophilic.
  • the second technical problem to be solved of the present invention is to provide a method for producing the negative electrode active material.
  • the third technical problem to be solved of the present invention is to provide a secondary battery negative electrode including the negative electrode active material.
  • a third technical problem to be solved by the present invention is to provide a secondary battery including the negative electrode, a battery module and a battery pack including the same.
  • An anode active material comprising artificial graphite surface-modified with a nitrogen atom
  • the nitrogen atom provides a negative electrode active material containing 5% by weight to 10% by weight based on the total weight of all the atoms present in the outermost portion of the negative electrode active material including artificial graphite.
  • step 1 Connecting the oxygen-containing functional group to the artificial graphite through a mild oxidation process (step 1); And
  • a negative electrode active material of the present invention comprising the step (step 2) of reducing the artificial graphite connected to the oxygen-containing functional group of the step 1 in a nitrogen atmosphere (step 2).
  • an embodiment of the present invention provides a secondary battery negative electrode on which a negative electrode active material slurry including the negative electrode active material is coated on a negative electrode current collector.
  • an embodiment of the present invention provides a secondary battery including the negative electrode, the positive electrode and the nonaqueous electrolyte, and a battery module and a battery pack including the same.
  • anode active material made of artificial graphite surface-modified with a specific amount of nitrogen element
  • the dispersibility in the aqueous system is improved, the affinity with the binder is high, the adhesive strength is increased, and the battery capacity is high.
  • a secondary battery negative electrode and a secondary battery including the same may implement the maintenance effect.
  • the negative electrode active material according to the present invention is connected to the surface of the artificial graphite by the oxygen-containing functional group only 10 to 20% by weight through a manufacturing method using a mild oxidation process, while exhibiting hydrophilicity, while maintaining the original crystallinity of the electrical conductor Therefore, it can exhibit excellent battery efficiency.
  • Example 1 is a photograph of an artificial graphite doped with nitrogen element prepared in step 2 of Example 1 under a scanning electron microscope (SEM).
  • FIG. 2 is a graph showing the result of measuring binding energy of the artificial graphite doped with nitrogen element prepared in Example 1 according to Experimental Example 4 and the surface-treated artificial graphite of Comparative Example 1.
  • FIG. 2 is a graph showing the result of measuring binding energy of the artificial graphite doped with nitrogen element prepared in Example 1 according to Experimental Example 4 and the surface-treated artificial graphite of Comparative Example 1.
  • Example 3 is an XRD graph measured by an X-ray diffraction analyzer for artificial graphite subjected to the mild oxidation process of Step 1 of Example 1 of the present invention.
  • Example 4 is an XRD graph measured by an X-ray diffraction analyzer for artificial graphite doped with nitrogen element of step 2 of Example 1 of the present invention.
  • FIG. 5 is an XRD graph of untreated surface graphite of Comparative Example 1.
  • the terms “comprise”, “comprise” or “have” are intended to indicate that there is a feature, number, step, component, or combination thereof, that is, one or more other features, It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.
  • artificial graphite Since artificial graphite is manufactured through high temperature heat treatment, all oxygen-containing functional groups present on the surface of artificial graphite are removed to have hydrophobic characteristics.
  • hydrophobic artificial graphite has various problems such as viscosity change and change over time in an aqueous system.
  • the present invention is intended to provide a more stable electrode by modifying the surface of the artificial graphite to hydrophilic, to exhibit excellent dispersibility in the aqueous system.
  • An anode active material comprising artificial graphite surface-modified with a nitrogen atom
  • the nitrogen atom provides a negative electrode active material containing 5% by weight to 10% by weight based on the total weight of all atoms present in the outermost part of the negative electrode active material including artificial graphite.
  • flaky artificial graphite having a diameter of 5 to 20 ⁇ m may be used.
  • the artificial graphite may be one or more selected from the group consisting of graphitized mesocarbon microbeads, graphitized mesophase pitch-based carbon fibers and graphitized coke, but the artificial graphite is not limited thereto.
  • the artificial graphite Since the artificial graphite is manufactured through a high temperature heat treatment, all the oxygen-containing functional groups present on the surface of the artificial graphite are removed to have hydrophobic characteristics. Because of this, hydrophobic artificial graphite causes various problems such as viscosity change and change over time in an aqueous system.
  • the present invention in order to solve the problem that the surface of the artificial graphite is hydrophobic, it provides a negative electrode active material by modifying the surface of the artificial graphite with nitrogen.
  • the content of nitrogen may be 5% by weight to 10% by weight relative to the weight of all the atoms present in the outermost portion of the negative electrode active material including the artificial graphite.
  • the degree (%) modified with nitrogen can be quantitatively analyzed through X-ray photoelectron spectroscopy (XPS).
  • the outermost range of the negative electrode active material means a thickness within 100 nm from the surface of the negative electrode active material, that is, the surface of the negative electrode active material located farthest from the center in the core direction.
  • the nitrogen element is modified to less than 5% by weight, the hydrophilicity is insufficient and the aqueous dispersibility is not improved, and the oxygen-containing functional groups are exposed a lot, which may cause electrochemical instability.
  • the side reactivity with the electrolyte may increase, which may cause problems of initial efficiency, capacity reduction, and deterioration of battery life.
  • a method of first modifying nitrogen using the oxygen-containing functional group may be used by lowering an energy barrier by connecting an oxygen-containing functional group to the surface of the artificial graphite.
  • the surface of the artificial graphite is -CH 2 or CH 3
  • one or more of the sites where the hydrogen is separated is replaced with an oxygen-containing functional group can be connected to the oxygen-containing functional group on the surface of the artificial graphite.
  • the surface of the artificial graphite can be finally modified with a nitrogen atom by doping nitrogen to the artificial graphite to which the oxygen-containing functional group is connected to replace the oxygen-containing functional group itself or a part of the oxygen-containing functional group with a nitrogen atom.
  • the oxygen-containing functional group may be used one or more selected from the group consisting of a hydroxyl group, an epoxy group, a carboxyl group and a lactol group, but is not limited thereto.
  • the oxygen-containing functional group may be linked in advance to a level equivalent to that of the modified nitrogen. Specifically, since the content of the modified nitrogen is about 5 to 10% by weight relative to the total weight of all the atoms present in the outermost portion of the negative electrode active material, the oxygen-containing functional group connected to the artificial graphite surface before the nitrogen modification is artificial About 10 to 20% by weight of the covalently bondable sites of the outermost carbon atoms of the graphite may be included in connection. In this case, the degree (substitution rate) of the oxygen-containing functional group connected to the surface of the artificial graphite can be quantitatively measured through an elemental analyzer.
  • the oxygen-containing functional group is connected to less than 10% by weight, there is a problem that artificial graphite cannot show hydrophilicity properly because the amount of nitrogen to be connected in the subsequent process is small, and too much if connected to more than 20% by weight. Since the amount of oxidation occurs, it is difficult to reduce all of them in a subsequent process, and the graphite layer is separated because the (002) surface of the artificial graphite is large, so that the capacity is small or the structure is not rigid, which is insufficient for a battery.
  • the oxygen-containing functional group may be connected to the surface of the artificial graphite by a mild oxidation process, which has been described in detail in the method for preparing the negative electrode active material.
  • the oxygen-containing functional group may be bonded at about 5 to 15% by weight based on the covalently bonded site of the outermost carbon atom of the artificial graphite in the negative electrode active material after nitrogen modification.
  • An anode active material comprising artificial graphite surface-modified with a nitrogen atom
  • 5 to 10 wt% may provide an oxygen-containing functional group in which a nitrogen atom or a portion is replaced by a nitrogen atom, 5 to 15 wt% of an oxygen-containing functional group, and 80 to 90 wt% of a negative electrode active material to which a hydrogen atom is bonded.
  • the surface of the artificial graphite used as the negative electrode active material has a low energy barrier, which makes it difficult to directly modify nitrogen. Therefore, in order to modify the surface of artificial graphite hydrophilically, a part of the surface of artificial graphite should be replaced with an oxygen-containing functional group to lower the energy barrier, and then nitrogen atoms should be connected using the oxygen-containing functional group.
  • the surface of the artificial graphite is -CH 2 or CH 3
  • one or more of the sites where the hydrogen is separated is replaced with an oxygen-containing functional group can be connected to the oxygen-containing functional group on the surface of the artificial graphite.
  • the oxygen-containing functional group itself or a part of the oxygen-containing functional group can be replaced with a nitrogen atom, and finally the outermost part of the artificial graphite can be modified with a nitrogen atom.
  • the content of the oxygen-containing functional group in which the nitrogen atom or part is replaced by a nitrogen atom may be 5 to 10% by weight relative to the covalently bonded site of the outermost carbon atom of artificial graphite.
  • the oxygen-containing functional group in which part of which is substituted with a nitrogen atom may eventually exhibit hydrophilicity because the nitrogen atom is present at the outermost part of the negative electrode active material.
  • the content of the nitrogen element or the nitrogen-substituted oxygen-containing functional group is less than 5% by weight, the hydrophilicity is insufficient, the aqueous dispersibility is not improved, and the oxygen-containing functional group is exposed a lot, which may cause electrochemical instability.
  • the content of the nitrogen element or nitrogen-substituted oxygen-containing functional group exceeds 10% by weight, side reaction with the electrolyte increases, which may cause problems of initial efficiency, capacity reduction, and deterioration of battery life.
  • the oxygen-containing functional group may also be connected to the equivalent level of 10 to 20% by weight. 25 to 50% by weight of the oxygen-containing functional group itself or a portion of the oxygen-containing functional group of the linked oxygen-containing functional group is replaced with nitrogen, the remaining of the oxygen-containing functional group that is not substituted with nitrogen on the surface of the negative electrode active material
  • the content may be 5 to 15% by weight, relative to the covalently linkable site of the outermost carbon atom of the artificial graphite.
  • the surface of the artificial graphite is present, the hydrogen atoms of the outermost because it is a -CH 2 or CH 3, oxygen-containing functional group and a negative electrode active material nitrogen is connected.
  • the negative electrode active material of the present invention may be 80 to 90% by weight of hydrogen atoms to the covalently bonded sites of the outermost carbon atoms of artificial graphite.
  • the interplanar spacing (d 002 ) of the carbon hexagonal net surface of the negative electrode active material according to the embodiment of the nitrogen-modified the present invention may be 0.3350 to 0.3400 nm. Since the negative electrode active material of the present invention is connected to the oxygen-containing functional group only on a portion of the surface of the artificial graphite, the surface of the artificial graphite is separated due to the connection of the excess oxygen-containing functional groups or the inter-plane distance increases to solve the problem of inferior crystallinity. In addition, the effect of exhibiting hydrophilicity can be realized while maintaining the original crystallinity of artificial graphite.
  • step 1 Connecting the oxygen-containing functional group to the artificial graphite through a mild oxidation process (step 1); And
  • It provides a method for producing a negative electrode active material comprising a; doping the nitrogen by reducing the artificial graphite connected to the oxygen-containing functional group of step 1 in a nitrogen atmosphere (step 2).
  • step 1 is a step of connecting a oxygen-containing functional group to the surface of the artificial graphite by performing a mild oxidation process before performing nitrogen doping to the artificial graphite.
  • the artificial graphite of (step 1) may be used at least one selected from the group consisting of graphitized mesocarbon microbeads, graphitized mesophase pitch-based carbon fiber and graphitized coke, but the artificial graphite is not limited thereto. . Since the surface of the artificial graphite has a low energy barrier and thus it is difficult to directly dope nitrogen, the surface of the artificial graphite may be doped with nitrogen after lowering the energy barrier by connecting an oxygen-containing functional group to the surface of the artificial graphite.
  • the mild oxidation of (step 1) means connecting the oxygen-containing functional group at a substitution rate of 10 to 20% by weight with respect to the covalently bonded site of the outermost carbon atom of artificial graphite. That is, the surface of the artificial graphite is -CH 2 or CH 3 , and the surface of the artificial graphite can be oxidized by connecting an oxygen-containing functional group to one or more of the hydrogen is separated.
  • step 1 If the oxygen-containing functional group of (step 1) is linked to the covalently bonded site of the outermost carbon atom of artificial graphite, artificial graphite is less because the amount of nitrogen connected in the subsequent process is less than 10% by weight. This hydrophilicity cannot be represented properly, and when connected at a substitution rate of more than 20% by weight, too much oxidation occurs, so that it is difficult to reduce all of them in a subsequent process, and the graphite layer becomes larger due to the (002) plane of artificial graphite. Because of the separation, the capacity is small, or the structure is not rigid, there is a problem that is insufficient for the battery.
  • the substitution rate indicating the extent to which the oxygen-containing functional group is connected to the surface of the artificial graphite can be measured quantitatively through an elemental analyzer.
  • the mild oxidation process of (step 1) may be performed by heat treating artificial graphite in an air atmosphere at 500 to 600 ° C. for 1 hour to 1 hour and / or immersing artificial graphite in an acid solution for 4 to 6 hours and then drying it. Can be.
  • the acid solution is a nitric acid solution of 50 to 70 °C concentration of 30 to 50% by weight
  • the drying is preferably carried out in a vacuum of 250 to 300 °C.
  • the oxygen-containing functional group can adjust its content by limited heat treatment time or immersion time of the acid solution. That is, in the method of the present invention, the oxygen-containing functional group content can be controlled within 10 to 20% by weight only after heat treatment or immersion under the above-described time conditions.
  • the heat treatment time or the immersion time in the acid solution is less than the time, the oxygen-containing functional group content is reduced, and thus the nitrogen element content is lowered so that the aqueous dispersibility is not improved, and the time is exceeded. Since the oxygen-containing functional group content is increased, and thus the nitrogen element content is increased, the side reaction with the electrolyte is increased, which may cause problems of initial efficiency, capacity reduction, and deterioration of battery life.
  • the oxygen-containing functional group of (step 1) may be at least one selected from the group consisting of a hydroxyl group, an epoxy group, a carboxyl group, and a lactol group, but the oxygen-containing functional group is not limited thereto.
  • step 2 is a step of doping nitrogen by reducing artificial graphite to which the oxygen-containing functional group of (step 1) is connected in a nitrogen atmosphere.
  • Step 2 is a step of replacing the oxygen-containing functional group itself or a part of the oxygen-containing functional group connected to artificial graphite by (Step 1) with a nitrogen element. Even though only the oxygen-containing functional group is attached to the surface of the artificial graphite, the artificial graphite may exhibit hydrophilicity, but the oxygen-containing functional group alone does not satisfy the electrochemical characteristics required by the secondary battery. Therefore, in order to overcome this, by doping the surface of the artificial graphite with a nitrogen element in which two non-covalent electron pairs exist through (step 2), it is possible to produce artificial graphite having not only excellent electrochemical properties but also a hydrophilic surface.
  • the (step 2) can be carried out in a gas atmosphere in which hydrogen gas is mixed with one gas selected from the group consisting of hydrazine (N 2 H 2 ), ammonia (NH 3 ) and mixtures thereof.
  • step (2) is carried out by reducing the hydrazine or ammonia gas and hydrogen gas in a nitrogen gas atmosphere in which 3: 3 is mixed, whereby the oxygen-containing functional group itself or part of the oxygen-containing functional group connected to the surface of the artificial graphite is nitrogen. It can be replaced by an element.
  • the (step 2) may be performed under a temperature condition of 800 to 1000 °C. Specifically, in the method of the present invention, the temperature is raised to a temperature of 800 to 1000 ° C. over about 5 hours, and then reacted for about 2 hours, followed by lowering the temperature for 12 hours.
  • the amount of nitrogen doping can be controlled by the limited gas composition and the temperature range and the temperature increase time and the reaction time.
  • the temperature range, the temperature and the reaction time are less than the range, there may occur a problem that the unreacted residual oxygen-containing functional group remains when the reaction is performed at a temperature below, for example, 800 ° C. or less than 2 hours. have.
  • the reaction is carried out at a temperature of more than 1000 °C or more than 2 hours, so that the side reactivity with the electrolyte increases, which leads to a decrease in initial efficiency, capacity reduction, and lifetime characteristics of the battery.
  • the problem may be that the doped portion is damaged.
  • another embodiment of the present invention provides a negative electrode on which a negative electrode active material slurry including the negative electrode active material is coated on a negative electrode current collector.
  • the negative electrode may be prepared by applying a negative electrode active material slurry including the negative electrode active material of the present invention on a negative electrode current collector, followed by drying and rolling.
  • the negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include copper, stainless steel, aluminum, nickel, titanium, calcined carbon; Or aluminum, stainless steel, etc. which surface-treated with carbon, nickel, titanium, silver, etc. can be used.
  • the negative electrode active material slurry may further include a binder as a component to assist in the bonding between the active material and the conductive material and the current collector.
  • the binder is not particularly limited, and for example, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetra
  • One selected from the group consisting of fluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluorine rubber, and mixtures thereof can be used.
  • the negative electrode active material slurry may further include a conductive material.
  • the conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery.
  • graphite Carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black
  • Conductive fibers such as carbon fibers and metal fibers
  • Metal powders such as carbon fluoride powder, aluminum powder and nickel powder
  • Conductive whiskeys such as zinc oxide and potassium titanate
  • Conductive metal oxides such as titanium oxide
  • Conductive materials such as polyphenylene derivatives and the like can be used.
  • the negative electrode active material according to the present invention is hydrophilic by doping with nitrogen, it may exhibit higher dispersibility in an aqueous system for preparing an electrode using an aqueous solvent such as water and alcohol.
  • an increase in the affinity between the active material and the aqueous binder improves the adhesive strength of the electrode, thereby providing a secondary battery having excellent electrical conductivity and stable for long-term use.
  • secondary graphite is modified to be hydrophilic by using nitrogen element, it is electrochemically stable, and the secondary battery including the secondary battery is excellent because the capacity of artificial graphite can be maintained by maintaining the interfacial distance of artificial graphite by mild mythification process. Can exhibit characteristics.
  • It provides a secondary battery including the negative electrode, a positive electrode, a separator interposed between the positive electrode and the separator and a nonaqueous electrolyte.
  • the positive electrode may be prepared by applying a positive electrode active material slurry including a positive electrode active material on a positive electrode current collector, followed by drying and rolling.
  • the positive electrode active material is not particularly limited, specifically, a lithium transition metal oxide may be used.
  • the lithium transition metal oxide include Li.Co-based composite oxides such as LiCoO 2 , Li.Ni.Co.Mn-based composite oxides such as LiNi x Co y Mn z O 2 , and Li.sub.2 such as LiNiO 2 .
  • Ni-based composite oxide may be mentioned, such as LiMn 2 O 4 of the Li-Mn composite oxide such, may be mixed alone or a plurality of them.
  • the positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include stainless steel, aluminum, nickel, titanium, calcined carbon; Or aluminum, stainless steel, etc. which surface-treated with carbon, nickel, titanium, silver, etc. can be used.
  • the positive electrode active material slurry may further include a binder.
  • the binder is not particularly limited, and for example, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetra
  • One selected from the group consisting of fluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluorine rubber, and mixtures thereof can be used.
  • the positive electrode active material slurry may further include the same or different conductive material as used in the negative electrode active material slurry.
  • the nonaqueous electrolyte may be composed of an electrolyte solution and a metal salt, and the nonaqueous organic solvent is used as the electrolyte solution.
  • non-aqueous organic solvent for example, N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butylo lactone, 1,2-dime Methoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolon, formamide, dimethylformamide, dioxoron, acetonitrile, nitromethane, methyl formate, Methyl acetate, phosphate triester, trimethoxy methane, dioxoron derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate Aprotic organic solvents, such as ethyl propionate,
  • the metal salt may be a lithium salt
  • the lithium salt is a material that is good to dissolve in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, 4-phenyl Lithium borate, imide and the like can be used.
  • a battery module including the secondary battery as a unit cell and a battery pack including the same are provided. Since the battery module and the battery pack include the secondary battery exhibiting stable and excellent battery characteristics, a power tool, an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in are included. It can be used as a power source of any one or more of the electric vehicle, including a plug-in hybrid electric vehicle (PHEV), or a system for power storage.
  • PHEV plug-in hybrid electric vehicle
  • Step 1 The oxygen-containing functional group was attached through a mild oxidation process in which flaky artificial graphite (product name: BTR S360) having a diameter in the range of 5-20 ⁇ m was heat-treated in an air atmosphere at 550 ° C. in a tube furnace.
  • flaky artificial graphite product name: BTR S360
  • Step 2 hydrazine (N 2 H 2 ) of 800 °C the artificial graphite attached to the oxygen-containing functional group Nitrogen element was doped to the surface of the artificial graphite through a process of reducing for 24 hours in a nitrogen gas atmosphere of 3: 7 gas and hydrogen gas mixed.
  • Step 3 The negative electrode active material slurry was prepared by mixing 96 g of the artificial graphite doped with nitrogen element, 1 g of CMC, an aqueous binder, 2 g of SBR, 1 g of acetylene black, a conductive material, and 220 g of water, a solvent.
  • the negative electrode active material slurry was applied to a copper current collector, and then dried and rolled in a vacuum oven at 130 ° C. to prepare a negative electrode.
  • Step 1 A negative electrode active material slurry was prepared by mixing 96 g of general artificial graphite without surface modification, 1 g of CMC as an aqueous binder, 2 g of SBR, 1 g of acetylene black as a conductive material and 220 g of water as a solvent.
  • the negative electrode mixture was coated on a copper current collector, dried in a vacuum oven at 130 ° C., and rolled to prepare a negative electrode.
  • the artificial graphite can be confirmed that the flaky form having a diameter in the range of 5 to 20 ⁇ m, it can be seen that the shape is maintained stable without breaking.
  • artificial graphite can serve as a stable anode active material even after the mild oxidation process and the nitrogen doping process.
  • Oxygen content at the outermost surface of the artificial graphite subjected to the mild oxidation process in step 1 of Example 1 was measured by an elemental analyzer, and the results are shown in Table 1.
  • the oxygen-containing functional group is connected at a substitution rate of 9 to 10% by weight with respect to the outermost surface of the artificial graphite.
  • X-ray photoelectron spectroscopy was used to measure the binding energy of the artificial graphite doped with the nitrogen element of (Step 2) of Example 1 and the surface-modified artificial graphite of Comparative Example 1 The results are shown in FIG.
  • the artificial graphite of Comparative Example 1 exhibits an even distribution of intensity in the energy range of 392 eV to 408 eV, whereas the artificial energy doped with nitrogen element of Example 1 has a binding energy of 396 eV. You can see that the intensity starts increasing and then decreases again at 404 eV.
  • the oxygen-containing functional group is connected to a part of the surface of the artificial graphite through the mild oxidation process, it can be confirmed that some or all of the oxygen-containing functional group is replaced with nitrogen, so that a certain amount of nitrogen is doped to the surface of the artificial graphite.
  • the nitrogen element doping concentration was calculated through the ratio of the peak area of carbon appearing between 280 and 292 eV and the peak area of nitrogen appearing between 396 eV and 404 eV. It was found that about 7.21 atom% of nitrogen was doped on the surface.
  • the interfacial distance of the artificial graphite of Comparative Example 1, which is not surface modified was 0.3372 nm (see FIG. 5), and the artificial oxidation process of performing the mild oxidation process of (Step 1) in Example 1 was performed.
  • the interplanar spacing of graphite was 0.3385 nm (see FIG. 3), and the interplanar spacing of artificial graphite further subjected to nitrogen element doping of (step 2) was 0.3377 nm (see FIG. 4).
  • the interfacial distance of artificial graphite increased by 0.38% compared to before the mild oxidation process, and then decreased by 0.23% after doping nitrogen element.
  • the artificial graphite of FIG. 4 surface-modified according to the method of the present invention has an artificial graphite having an interplanar distance difference of about 0.1% compared to the artificial graphite of Comparative Example 1 of FIG. .
  • the mild oxidation process and nitrogen element doping of the artificial graphite can be performed hydrophilic treatment without significant change in the structure of the artificial graphite.
  • the artificial graphite which is not surface-modified as in Comparative Example 1 is inferior in dispersibility, so that the artificial graphite is not evenly dispersed in the solvent and sinks to the lower liquid, so that the weight of the solid remaining even when the supernatant is evaporated is small.
  • nitrogen-doped artificial graphite has improved hydrophilicity and excellent dispersibility in an aqueous system, it is dispersed evenly in both the supernatant and the supernatant in the solvent, so that a large amount remains even after the supernatant is evaporated. It can be predicted.
  • the adhesion of the negative electrode of Example 1 of the present invention is 30 gf / 15 mm, 2.3 times compared to the negative electrode (13 gf / 15 mm) of Comparative Example 1 using the surface-modified artificial graphite It can be seen that it has excellent adhesion.
  • the secondary battery having excellent adhesive strength and high electrical conductivity and stable for long-term use is provided. It can be predicted that it can be done.

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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
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Abstract

La présente invention se rapporte à un matériau actif d'électrode négative et à un procédé permettant de préparer ce dernier et, de façon plus précise, à un matériau actif d'électrode négative obtenu par modification d'une surface de graphite artificiel avec des atomes d'azote, les atomes d'azote présentant une teneur comprise entre 5 et 10 % en poids sur la base de tous les atomes existant dans la coque la plus extérieure du matériau actif d'électrode négative. Le matériau actif d'électrode négative selon la présente invention, qui est obtenu par modification d'une surface de graphite artificiel avec de l'azote, présente une meilleure dispersibilité dans un système aqueux de sorte que l'affinité entre un liant et le matériau actif d'électrode négative soit améliorée, ce qui permet d'augmenter la force de liaison d'une électrode. De plus, seule une quantité particulière de la surface du graphite artificiel est modifiée avec de l'azote, et, ainsi, la capacité de la batterie est maintenue à un niveau élevé. En outre, dans le procédé permettant de préparer un matériau actif d'électrode négative selon la présente invention, seulement 10 à 20 % en poids d'un groupe fonctionnel contenant de l'oxygène sont liés au graphite artificiel au moyen d'un procédé d'oxydation douce, de telle sorte que l'azote soit facilement fixé au graphite artificiel pour permettre au graphite artificiel de présenter un caractère hydrophile, et le graphite artificiel devient un conducteur électrique en raison de la conservation de sa cristallinité d'origine, ce qui permet d'obtenir une excellente efficacité de batterie.
PCT/KR2016/003926 2015-04-15 2016-04-15 Matériau actif d'électrode négative et procédé permettant de préparer ce dernier Ceased WO2016167591A1 (fr)

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US12080878B2 (en) 2020-10-15 2024-09-03 Samsung Sdi Co., Ltd. Anode layer for all-solid secondary battery, all-solid secondary battery including the same, and method of manufacturing all-solid secondary battery
WO2025135798A1 (fr) * 2023-12-21 2025-06-26 주식회사 엘지에너지솔루션 Matériau actif d'électrode négative, et électrode négative et batterie rechargeable le comprenant

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Publication number Priority date Publication date Assignee Title
CN108249923A (zh) * 2017-12-22 2018-07-06 中国平煤神马集团开封炭素有限公司 一种石墨电极接头糊料及其制备方法
US12080878B2 (en) 2020-10-15 2024-09-03 Samsung Sdi Co., Ltd. Anode layer for all-solid secondary battery, all-solid secondary battery including the same, and method of manufacturing all-solid secondary battery
WO2024159930A1 (fr) * 2023-02-03 2024-08-08 宁德时代新能源科技股份有限公司 Matériau actif d'électrode négative en carbone et son procédé de préparation, batterie secondaire et dispositif électrique
WO2025135798A1 (fr) * 2023-12-21 2025-06-26 주식회사 엘지에너지솔루션 Matériau actif d'électrode négative, et électrode négative et batterie rechargeable le comprenant

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