WO2024032173A1 - 一种锂离子电池 - Google Patents

一种锂离子电池 Download PDF

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Publication number
WO2024032173A1
WO2024032173A1 PCT/CN2023/102545 CN2023102545W WO2024032173A1 WO 2024032173 A1 WO2024032173 A1 WO 2024032173A1 CN 2023102545 W CN2023102545 W CN 2023102545W WO 2024032173 A1 WO2024032173 A1 WO 2024032173A1
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lithium
ion battery
carbonate
positive electrode
battery according
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PCT/CN2023/102545
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English (en)
French (fr)
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刘中波
黄雄
严思文
郑仲天
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深圳新宙邦科技股份有限公司
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Publication of WO2024032173A1 publication Critical patent/WO2024032173A1/zh

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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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • 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
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • 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 invention belongs to the technical field of energy storage devices, and specifically relates to a lithium-ion battery.
  • Lithium-ion batteries are a new generation of rechargeable batteries following traditional batteries such as nickel metal hydride. They were first successfully developed by Japan's Sony Corporation in 1990. Lithium-ion batteries have a simple working principle, good safety, long charge and discharge life, high operating voltage, high energy density, small size, long cycle life, and wide operating temperature range, and are widely used.
  • lithium-ion batteries can start from the following aspects: 1) increase the gram capacity of the cathode material; 2) increase the battery discharge platform; 3) increase the proportion of active materials in the battery; and so on.
  • Increasing the charging cut-off voltage of lithium-ion batteries is one of the important ways to increase battery energy density, because as the charging cut-off voltage increases, the cathode material can achieve higher gram capacity, and the discharge platform is significantly improved, in two aspects has an immediate effect on increasing energy density.
  • Lithium cobalt oxide is the cathode material currently used in high-voltage batteries. As the battery voltage gradually increases, the cathode material enters a higher delithiation state, the structural stability of the material becomes worse, and the oxidation of the surface also increases significantly. . With the development of high-gram capacity cathode materials, the instability of the material structure and its high oxidation are particularly obvious at the electrode plate/non-aqueous electrolyte interface. Among them, the Co element in lithium cobalt oxide is very important for catalyzing the non-aqueous electrolyte. Decomposition has an important impact, specifically as follows: the battery produces gas, the internal resistance increases rapidly, and the capacity drops sharply. More importantly, it will lead to a decrease in the safety performance of the battery. During the battery hot box safety test, the battery will explode, burn and other dangerous situations, so it is necessary to match the non-aqueous electrolyte with better safety performance.
  • LCO Lithium cobalt oxide
  • the other is to choose flame retardant additives to improve the flame retardant effect of the non-aqueous electrolyte, thereby inhibiting the combustion of the non-aqueous electrolyte and improving safety performance.
  • both methods significantly degrade the regular performance cycle and storage performance of the full battery, and cannot effectively balance regular performance and safety performance.
  • the present invention provides a lithium ion battery.
  • the invention provides a lithium ion battery, which includes a positive electrode, a negative electrode and a non-aqueous electrolyte.
  • the positive electrode includes a positive electrode current collector and a positive electrode material layer disposed on the positive electrode current collector.
  • the positive electrode material layer includes cobalt acid. Lithium cathode active material, the thermal failure temperature of the cathode T 0 >220°C, the non-aqueous electrolyte including non-aqueous organic solvent, lithium salt and additives, the additives including the compound represented by Structural Formula 1:
  • n 0 or 1
  • A is selected from C or O
  • X is selected from R 1 and R 2 are each independently selected from H, R 1 and R 2 are not selected from H at the same time, and X, R 1 and R 2 contain at least one sulfur atom;
  • the lithium-ion battery meets the following conditions:
  • a is the mass percentage content of Co in the cathode material layer, the unit is %;
  • b is the specific surface area of the positive active material, in m 2 /g;
  • c is the mass percentage content of the compound represented by Structural Formula 1 in the non-aqueous electrolyte, and the unit is %.
  • the lithium-ion battery meets the following conditions:
  • the specific surface area b of the cathode active material is 0.15 to 0.5 m 2 /g.
  • the mass percentage content c of the compound represented by Structural Formula 1 in the non-aqueous electrolyte solution is 0.5 to 2.5%.
  • the charging voltage of the lithium-ion battery is ⁇ 4.48V.
  • the compound represented by the structural formula 1 is selected from one or more of the following compounds:
  • the non-aqueous organic solvent includes ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, butyl acetate, ⁇ -butyrolactone, propyl propionate, propylene carbonate, etc.
  • ethylene carbonate dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, butyl acetate, ⁇ -butyrolactone, propyl propionate, propylene carbonate, etc.
  • the lithium salt includes LiPF 6 , LiBOB, LiDFOB, LiPO 2 F 2 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiC(SO 2 CF 3 ) 3 , LiN(SO 2 F) 2 , LiClO 4 , LiAlCl 4 , LiCF 3 SO 3 , Li 2 B 10 Cl 10 , LiSO 3 F, LiTOP, LiDODFP, LiOTF and lower aliphatic carboxylic acids At least one of the lithium salts.
  • the additive also includes at least one of cyclic sulfate ester compounds, sultone compounds, cyclic carbonate compounds, phosphate ester compounds, borate ester compounds and nitrile compounds;
  • the content of the additive is 0.01% to 30%.
  • the cyclic sulfate compound is selected from vinyl sulfate, propylene sulfate, vinyl methyl sulfate, at least one of;
  • the sultone compound is selected from 1,3-propane sultone, 1,4-butane sultone, and 1,3-propene sultone. at least one of;
  • the cyclic carbonate compound is selected from vinylene carbonate, ethylene ethylene carbonate, methylene vinyl carbonate, fluoroethylene carbonate, trifluoromethylethylene carbonate, bisfluoroethylene carbonate or structural formula At least one of the compounds shown in 2,
  • R 21 , R 22 , R 23 , R 24 , R 25 , and R 26 are each independently selected from one of hydrogen atoms, halogen atoms, and C1-C5 groups;
  • the phosphate compound is selected from at least one of tris(trimethylsilane)phosphate, tris(trimethylsilane)phosphite or the compound represented by structural formula 3:
  • R 31 , R 32 , and R 33 are each independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, -Si(C m H 2m+1 ) 3 , and m is 1 to is a natural number of 3, and at least one of R 31 , R 32 , and R 33 is an unsaturated hydrocarbon group;
  • the borate compound is selected from at least one of tris(trimethylsilane)borate and tris(triethylsilane)borate;
  • the nitrile compound is selected from succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelonitrile, and sebaconitrile. of at least one.
  • lithium cobalt oxide is used as the positive electrode active material, so that the lithium ion battery has a higher energy density.
  • the compound represented by the structural formula 1 is added to the non-aqueous electrolyte.
  • the compound represented by the structural formula 1 can The film formed on the surface of the cathode material layer has an anchoring effect on the Co element in the cathode active material. It can anchor the Co element in the crystal structure of the cathode active material to prevent the Co element from affecting the non-aqueous electrolyte in the cathode material layer.
  • the mass percentage content c and the specific surface area b of the cathode active material can control the film-forming quality of the compound shown in structural formula 1 on the cathode material layer.
  • the three can achieve a better coordination effect and can effectively suppress Co catalyzes the side reaction of the non-aqueous electrolyte, further inhibiting the migration of lattice oxygen in the cathode active material, ultimately preventing the non-aqueous electrolyte from continuously producing gas and causing fire and explosion, effectively improving the safety performance and cycle performance of the hot box.
  • the invention provides a lithium ion battery, which includes a positive electrode, a negative electrode and a non-aqueous electrolyte.
  • the positive electrode includes a positive electrode current collector and a positive electrode material layer disposed on the positive electrode current collector.
  • the positive electrode material layer includes cobalt acid. Lithium cathode active material, the thermal failure temperature of the cathode T 0 >220°C, the non-aqueous electrolyte including non-aqueous organic solvent, lithium salt and additives, the additives including the compound represented by Structural Formula 1:
  • n 0 or 1
  • A is selected from C or O
  • X is selected from R 1 and R 2 are each independently selected from H, R 1 and R 2 are not selected from H at the same time, and X, R 1 and R 2 contain at least one sulfur atom;
  • the lithium-ion battery meets the following conditions:
  • a is the mass percentage content of Co in the cathode material layer, the unit is %;
  • b is the specific surface area of the positive active material, in m 2 /g;
  • c is the mass percentage content of the compound represented by Structural Formula 1 in the non-aqueous electrolyte, and the unit is %.
  • the lithium-ion battery uses lithium cobalt oxide as the cathode active material, so that the lithium-ion battery has a higher energy density.
  • the compound represented by structural formula 1 is added to the non-aqueous electrolyte.
  • the compound represented by structural formula 1 can be added to the cathode material layer.
  • the surface film formation has an anchoring effect on the Co element in the cathode active material, and can anchor the Co element in the crystal structure of the cathode active material to avoid the influence of Co element on the non-aqueous electrolyte at the interface of the cathode material layer.
  • the inventor found through extensive research that when the mass percentage content a of Co in the cathode material layer affects the catalytic decomposition of the non-aqueous electrolyte, by controlling the mass percentage of the compound represented by Structural Formula 1 in the non-aqueous electrolyte
  • the content c and the specific surface area b of the cathode active material can control the film-forming quality of the compound shown in structural formula 1 on the cathode material layer.
  • the three work together to affect the safety and cycle performance of lithium-ion batteries under high temperature conditions.
  • the cathode When the cathode The mass percentage content a of Co in the material layer, the specific surface area b of the cathode active material, and the mass percentage content c of the compound represented by structural formula 1 in the non-aqueous electrolyte satisfies When the conditions are 0.01 ⁇ 10c/(a*b) ⁇ 9, and 57 ⁇ a ⁇ 60, 0.1 ⁇ b ⁇ 0.8, 0.01 ⁇ c ⁇ 5.5, the three can achieve a better coordination effect and can effectively inhibit Co catalyzed non-aqueous
  • the side reaction of the electrolyte further inhibits the migration of lattice oxygen in the positive active material, ultimately preventing the non-aqueous electrolyte from continuously producing gas and causing fire and explosion, effectively improving the safety performance and cycle performance of the hot box.
  • the lithium-ion battery meets the following conditions: 0.25 ⁇ 10c/(a*b) ⁇ 2.5.
  • the influence of the mass percentage content a of Co in the cathode material layer, the specific surface area b of the cathode active material, and the mass percentage content c of the compound represented by Structural Formula 1 in the non-aqueous electrolyte solution on battery performance can be further integrated. , improve the safety performance and cycle performance of lithium-ion batteries.
  • the mass percentage content a of Co in the cathode material layer can be 57%, 57.3%, 57.5%, 57.8%, 58%, 58.3%, 58.5%, 58.8%, 59%, 59.3% , 59.5%, 59.8% or 60%.
  • the mass percentage a of Co in the cathode material layer is related to the lithium cobalt oxide contained in the cathode material layer. As the mass percentage a of Co in the cathode material layer increases, the energy density of the cathode increases accordingly. , at the same time, the Co element content on the surface of the cathode material layer increases, and the side reactions of the non-aqueous electrolyte intensify. Correspondingly, the specific surface area b of the cathode active material and the quality of the compound represented by Structural Formula 1 in the aqueous non-aqueous electrolyte can be controlled. The percentage content c regulates the side reactions of the non-aqueous electrolyte.
  • the specific surface area b of the positive active material can be 0.1m 2 /g, 0.12m 2 /g, 0.15m 2 /g, 0.18m 2 /g, 0.1m 2 /g, 0.2m 2 /g, 0.4m 2 /g, 0.5m 2 /g, 0.6m 2 /g, 0.7m 2 /g or 0.8m 2 /g.
  • the specific surface area b of the cathode active material is 0.15 to 0.5 m 2 /g.
  • the deintercalation reaction of lithium ions is mainly concentrated at the cathode material layer/non-aqueous electrolyte interface.
  • the increase in specific surface area can also easily lead to insufficient structural strength of the positive electrode material layer, causing the material to fall off. The problem also aggravates the decomposition of the non-aqueous electrolyte.
  • the specific surface area b of the positive electrode active material also directly affects the film thickness of the compound represented by structural formula 1 per unit mass on the surface of the positive electrode material layer, which is related to non-aqueous electrolysis.
  • the contents of the compounds represented by structural formula 1 in the liquid are related to each other.
  • the mass percentage content c of the compound represented by Structural Formula 1 in the non-aqueous electrolyte solution can be 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.4%, 0.5% , 0.7%, 0.9%, 1.0%, 1.1%, 1.3%, 1.5%, 1.8%, 2.0%, 2.3%, 2.7%, 3.0%, 3.3%, 3.7%, 4.0%, 4.3%, 4.7%, 5.0 % or 5.5%.
  • the mass percentage content c of the compound represented by Structural Formula 1 in the non-aqueous electrolyte solution is 0.5 to 2.5%.
  • the mass percentage content of the compound represented by Structural Formula 1 in the non-aqueous electrolyte is too low, it will not be conducive to the formation of a stable interface film on the surface of the cathode material layer, causing the cathode active material to have Co ion dissolution problems, and Co ions will elute. Prompt the positive electrode material to intensify the phase transformation and accumulate internal stress, leading to amorphization of the material and structural collapse and rupture, which in turn leads to battery capacity attenuation; if the mass percentage of the compound represented by Structural Formula 1 in the non-aqueous electrolyte is too high, It will cause the formed interface film to be too thick and increase the impedance of the battery.
  • the mass percentage content of the compound represented by Structural Formula 1 in the non-aqueous electrolyte is within the above range, it is beneficial to form a kind of The high ionic conductivity and stable interface film promotes the diffusion of lithium ions and effectively anchors the Co element in the cathode active material to improve the cycle performance of the battery.
  • the charging voltage of the lithium-ion battery is ⁇ 4.48V.
  • the compound represented by Structural Formula 1 is selected from one or more of the following compounds:
  • the lithium-ion battery is a pouch battery or a hard-shell battery.
  • the cathode material layer further includes a cathode binder.
  • the cathode binder includes polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, and vinylidene fluoride-hexafluoropropylene.
  • copolymer tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, Copolymer of vinylidene fluoride-trifluoroethylene, copolymer of vinylidene fluoride-trichloroethylene, copolymer of vinylidene fluoride-vinyl fluoride, copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyethylene Thermoplastic resins such as imide, polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate; acrylic resin; sodium carboxymethylcellulose; nitrile rubber, polybutadiene rubber, ethylene -Propylene rubber, styrene-but
  • the cathode material layer further includes a cathode conductive agent
  • the cathode conductive agent includes conductive carbon black, conductive carbon balls, conductive graphite, conductive carbon fiber, carbon nanotubes, graphene or reduced graphene oxide. one or more.
  • the positive electrode current collector is selected from metal materials that can conduct electrons.
  • the positive electrode current collector includes one or more of Al, Ni, tin, copper, and stainless steel.
  • the positive electrode current collector is selected from aluminum foil.
  • the negative electrode includes a negative electrode material layer including a negative electrode active material.
  • the negative active material includes at least one of a carbon-based negative electrode, a silicon-based negative electrode, a tin-based negative electrode, and a lithium negative electrode.
  • the carbon-based negative electrode can include graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, etc.
  • the silicon-based negative electrode can include silicon materials, silicon oxides, silicon-carbon composite materials, silicon alloy materials, etc.
  • the tin-based negative electrode can It can include tin, tin carbon, tin oxide, and tin metal compounds
  • the lithium negative electrode can include metallic lithium or lithium alloy.
  • the lithium alloy may specifically be at least one of lithium silicon alloy, lithium sodium alloy, lithium potassium alloy, lithium aluminum alloy, lithium tin alloy and lithium indium alloy.
  • the negative electrode material layer further includes a negative electrode binder and a negative electrode conductive agent, and the negative electrode active material, the negative electrode binder and the negative electrode conductive agent are blended to obtain the negative electrode material layer.
  • the selectable ranges of the negative electrode binder and the negative electrode conductive agent are the same as those of the positive electrode binder and the positive electrode conductive agent respectively, and will not be described again here.
  • the negative electrode further includes a negative electrode current collector, and the negative electrode material layer is formed on a surface of the negative electrode current collector.
  • the negative electrode current collector is selected from metal materials that can conduct electrons.
  • the negative electrode current collector includes one or more of Al, Ni, tin, copper, and stainless steel.
  • the negative electrode current collector is selected from copper foil.
  • the lithium salt includes LiPF 6 , LiBOB, LiDFOB, LiPO 2 F 2 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2.
  • LiC(SO 2 CF 3 ) 3 LiN(SO 2 F) 2 , LiClO 4 , LiAlCl 4 , LiCF 3 SO 3 , Li 2 B 10 Cl 10 , LiSO 2 F, LiTOP, LiDODFP, LiOTF and lower aliphatic At least one of lithium carboxylate salts.
  • the concentration of the lithium salt in the non-aqueous electrolyte is 0.1 mol/L to 8 mol/L. In a preferred embodiment, the concentration of the lithium salt in the non-aqueous electrolyte is 0.5 mol/L to 2.5 mol/L. Specifically, in the non-aqueous electrolyte solution, the concentration of the lithium salt can be 0.5 mol/L, 1 mol/L, 1.5 mol/L, 2 mol/L, or 2.5 mol/L.
  • the non-aqueous organic solvent includes one or more of ether solvents, nitrile solvents, carbonate solvents and carboxylate solvents.
  • ether solvents include cyclic ethers or chain ethers, preferably chain ethers with 3 to 10 carbon atoms and cyclic ethers with 3 to 6 carbon atoms.
  • Cyclic ethers can be, but are not limited to, It is 1,3-dioxopentane (DOL), 1,4-dioxane (DX), crown ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH 3 -THF), 2-trihydrofuran One or more of fluoromethyltetrahydrofuran (2-CF 3 -THF); the chain ether can be, but is not limited to, dimethoxymethane, diethoxymethane, ethoxymethoxymethane , Ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether.
  • chain ethers have high solvating power with lithium ions and can improve ion dissociation
  • dimethoxymethane, diethoxymethane, and ethoxymethoxy are particularly preferred because they have low viscosity and can impart high ionic conductivity.
  • Methane One type of ether compound may be used alone, or two or more types of ether compounds may be used in any combination and ratio.
  • the content of the ether compound is not particularly limited and is arbitrary within the range that does not significantly damage the effect of the high-pressure lithium ion battery of the present invention. When the non-aqueous solvent volume ratio is 100%, the volume ratio is usually 1% or more, and the volume ratio is preferred.
  • the volume ratio is 2% or more, and more preferably the volume ratio is 3% or more.
  • the volume ratio is usually 30% or less, preferably 25% or less, and more preferably 20% or less.
  • the total amount of the ether compounds may satisfy the above range.
  • the content of the ether compound is within the above-mentioned preferred range, it is easy to ensure the improvement effect of the ion conductivity by increasing the lithium ion dissociation degree and reducing the viscosity of the chain ether.
  • the negative electrode active material is a carbon-based material, the phenomenon of co-intercalation of chain ether and lithium ions can be suppressed, so the input-output characteristics and charge-discharge rate characteristics can be achieved within an appropriate range.
  • the nitrile solvent may be, but is not limited to, one or more of acetonitrile, glutaronitrile, and malononitrile.
  • the carbonate solvent includes cyclic carbonate or chain carbonate.
  • the cyclic carbonate can be, but is not limited to, ethylene carbonate (EC), propylene carbonate (PC), and ⁇ -butyrolactone.
  • EC ethylene carbonate
  • PC propylene carbonate
  • ⁇ -butyrolactone One or more of (GBL), butylene carbonate (BC);
  • the chain carbonate can be, but is not limited to, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) ), one or more of dipropyl carbonate (DPC).
  • DMC dimethyl carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • DPC dipropyl carbonate
  • the content of the cyclic carbonate is not particularly limited and is arbitrary within the range that does not significantly damage the effect of the lithium ion battery of the present invention.
  • the lower limit of the content is relative to the total amount of solvent in the non-aqueous electrolyte.
  • the volume ratio is 3% or more, and preferably the volume ratio is 5% or more.
  • the upper limit of the volume ratio is usually 90% or less, preferably 85% or less, and more preferably 80% or less.
  • the content of the chain carbonate is not particularly limited, but is usually 15% or more by volume, preferably 20% or more, and more preferably 25% or more by volume relative to the total amount of solvent in the non-aqueous electrolyte solution.
  • the volume ratio is usually 90% or less, preferably 85% or less, and more preferably 80% or less.
  • the content of the chain carbonate By setting the content of the chain carbonate within the above range, it is easy to bring the viscosity of the non-aqueous electrolyte solution into an appropriate range, thereby suppressing the decrease in ionic conductivity, thereby contributing to increasing the output of the non-aqueous electrolyte battery. Characteristics reach a good range. When two or more linear carbonates are used in combination, the total amount of the linear carbonates may satisfy the above range.
  • chain carbonates having fluorine atoms may also be preferably used.
  • the number of fluorine atoms contained in the fluorinated linear carbonate is not particularly limited as long as it is 1 or more, but it is usually 6 or less, preferably 4 or less.
  • these fluorine atoms may be bonded to the same carbon or to different carbons.
  • the fluorinated chain carbonate include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, and fluorinated diethyl carbonate derivatives.
  • Carboxylic acid ester solvents include cyclic carboxylic acid esters and/or chain carbonic acid esters.
  • cyclic carboxylic acid esters include one or more of ⁇ -butyrolactone, ⁇ -valerolactone, and ⁇ -valerolactone.
  • chain carbonates include methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate. of one or more.
  • the sulfone solvent includes cyclic sulfone and chain sulfone.
  • cyclic sulfone it usually has 3 to 6 carbon atoms, preferably 3 to 5 carbon atoms.
  • chain sulfone In the case of sulfone, it is usually a compound having 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms.
  • the content of the sulfone solvent is not particularly limited and is arbitrary as long as it does not significantly damage the effect of the lithium-ion battery of the present invention.
  • the volume ratio relative to the total amount of solvent in the non-aqueous electrolyte is usually 0.3% or more, and preferably the volume ratio is 0.5.
  • the volume ratio is 1% or more.
  • the volume ratio is usually 40% or less, preferably 35% or less, and more preferably 30% or less.
  • the non-aqueous organic solvent includes ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, propylene carbonate, butyl acetate, ⁇ -butyrolactone, propionic acid At least one of ester, ethyl propionate, ethyl butyrate, methyl acetate, ethyl acetate, ethyl fluoroacetate and fluoroether.
  • the non-aqueous organic solvent is a mixture of cyclic carbonate and chain carbonate.
  • the additive further includes at least one of cyclic sulfate ester compounds, sultone compounds, cyclic carbonate compounds, phosphate ester compounds, borate ester compounds and nitrile compounds. ;
  • the content of the additive is 0.01% to 30%.
  • the cyclic sulfate compound is selected from vinyl sulfate, propylene sulfate, vinyl methyl sulfate, at least one of;
  • the sultone compound is selected from at least one of 1,3-propane sultone, 1,4-butane sultone, and 1,3-propene sultone;
  • the cyclic carbonate compound is selected from vinylene carbonate, ethylene ethylene carbonate, methylene vinyl carbonate, fluoroethylene carbonate, trifluoromethylethylene carbonate, bisfluoroethylene carbonate or structural formula At least one of the compounds shown in 2,
  • R 21 , R 22 , R 23 , R 24 , R 25 , and R 26 are each independently selected from one of hydrogen atoms, halogen atoms, and C1-C5 groups;
  • the phosphate compound is selected from at least one of tris(trimethylsilane)phosphate, tris(trimethylsilane)phosphite or the compound represented by structural formula 3:
  • R 31 , R 32 , and R 33 are each independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, -Si(C m H 2m+1 ) 3 , and m is 1 to is a natural number of 3, and at least one of R 31 , R 32 , and R 33 is an unsaturated hydrocarbon group;
  • the phosphate compound represented by the structural formula 3 may be tripropargyl phosphate, dipropargyl methyl phosphate, dipropargyl ethyl phosphate, or dipropargyl propyl phosphate.
  • Phosphate ester dipropargyl trifluoromethyl phosphate, dipropargyl-2,2,2-trifluoroethyl phosphate, dipropargyl-3,3,3-trifluoropropyl phosphate, Dipropargyl hexafluoroisopropyl phosphate, triallyl phosphate, diallyl methyl phosphate, diallylethyl phosphate, diallyl propyl phosphate, diallyl triphosphate Fluoromethylphosphate, diallyl-2,2,2-trifluoroethylphosphate, diallyl-3,3,3-trifluoropropylphosphate, diallylhexafluoroisopropyl At least one of the base phosphates;
  • the borate compound is selected from at least one of tris(trimethylsilane)borate and tris(triethylsilane)borate;
  • the nitrile compound is selected from succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelonitrile, and sebaconitrile. of at least one.
  • the additives may also include other additives that can improve battery performance: for example, additives that improve battery safety performance, specifically flame retardant additives such as fluorinated phosphates, cyclophosphazene, or tert-amylbenzene. , tert-butylbenzene and other anti-overcharge additives.
  • the content of any optional substance in the additive in the non-aqueous electrolyte is less than 10%, preferably, the content is 0.1-5%, and more preferably, The content is 0.1% to 2%.
  • the content of any optional substance in the additive can be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8%, 8.5%, 9%, 9.5%, 10%.
  • the content of the fluorinated ethylene carbonate is 0.05% to 30% based on the total mass of the non-aqueous electrolyte being 100%.
  • the lithium ion battery further includes a separator, and the separator is located between the positive electrode and the negative electrode.
  • the separator can be an existing conventional separator, and can be a ceramic separator, a polymer separator, a non-woven fabric, an inorganic-organic composite separator, etc.
  • the polymer separator is selected from the group consisting of polyolefins, polyamides, polysulfones, and polyesters.
  • One or more of phosphazenes, polyethersulfones, polyetheretherketones, polyetheramides and polyacrylonitriles including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene ), double-layer PP/PE, double-layer PP/PP and three-layer PP/PE/PP separators.
  • the separator includes a base separator and a surface coating.
  • the surface coating is inorganic particles or organic gels or a mixture of the two and is coated on at least one side surface of the base separator.
  • This example is used to illustrate the preparation method of the lithium-ion battery disclosed in the present invention, which includes the following steps:
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • LiPF 6 lithium hexafluorophosphate
  • the cathode active material lithium cobalt oxide LiCoO 2 conductive carbon black Super-P and binder polyvinylidene fluoride (PVDF), and then disperse them in N-methyl-2-pyrrolidone (NMP) to obtain the cathode slurry.
  • NMP N-methyl-2-pyrrolidone
  • the slurry is evenly coated on both sides of the aluminum foil, dried, rolled and vacuum dried, and the aluminum lead wire is welded with an ultrasonic welder to obtain a positive plate.
  • the thickness of the plate is 120-150 ⁇ m, in which the positive material layer
  • the mass percentage of Co and the specific surface area of the cathode active material LiCoO2 are shown in Table 2.
  • a negative electrode slurry is obtained.
  • the slurry is coated on both sides of the copper foil, dried, rolled and vacuum dried, and a nickel lead wire is welded with an ultrasonic welder to obtain a negative plate with a thickness of 120-150 ⁇ m.
  • the nonaqueous electrolyte prepared above was injected into the battery core, sealed in a vacuum, and left to rest for 24 hours.
  • Examples 2 to 23 are used to illustrate the lithium-ion battery and its preparation method disclosed in the present invention, including most of the operating steps in Example 1, and the differences are:
  • Comparative Examples 1 to 11 are used to comparatively illustrate the lithium-ion battery disclosed in the present invention and its preparation method, including most of the operating steps in Example 1, and the differences are:
  • Capacity retention rate % discharge capacity of the last cycle / discharge capacity of the first cycle * 100%
  • Impedance growth rate % (impedance of the last circle - impedance of the first circle) / impedance of the first circle * 100%
  • Thermal failure temperature T 0 test of the positive electrode After the non-aqueous electrolyte is added to the battery and formed, charge it to 4.48V with a constant current and voltage of 0.2C, and the cut-off current is 0.03C; in the glove box, dissect the battery, separate the positive and negative electrodes, and use scissors Cut the positive electrode sheet; rinse the positive electrode sheet with DMC, wait until the positive electrode sheet is dry, put it into the crucible, and add 5 microliters of non-aqueous electrolyte dropwise, remove it from the glove box, and wait for testing. Test conditions: 25-150°C: 5°C/min; 150-350°C: 2.5°C/min, nitrogen atmosphere, test the thermal failure temperature T 0 of the positive electrode.
  • Hot box safety performance test The battery is formed according to the aforementioned formation conditions. The formed battery is charged with a constant current of 0.5C to 4.48V, then charged with a constant voltage until the current drops to 0.03C, and then discharged with a constant current of 0.5C. to 3.0V, use this procedure to cycle the battery 5 times at room temperature 25°C to calculate the battery discharge capacity. If the discharge capacity deviation is ⁇ 10mAh/g, then the battery is charged with a constant current of 0.5C to 4.48V and then charged with a constant voltage until the current drops. to 0.03C, as the battery's full charge state. Place the fully charged battery in the GX-3020-BL40 thermal shock test chamber.
  • the hot box works according to the set program "heating from 25°C to 130°C at 5°C/min and holding for 30min".
  • the "Data Collection Instrument” panel The temperature channel and voltage channel start recording real-time data. During the test, if the battery surface temperature detected by the data collector does not exceed 200°C, the voltage drop does not exceed 0.3V, and the battery does not explode or catch fire, then the hot box passes OK, otherwise it is NG.
  • the thickness of the interface film on the surface of the cathode material layer is correlated with the mass percentage content a of Co in the cathode material layer.
  • Co When it contains a higher content of When Co is used, it has stronger catalytic properties and requires a thicker interfacial film to anchor the Co element.
  • the three work together to inhibit the side reactions of the Co-catalyzed non-aqueous electrolyte and further inhibit the migration of lattice oxygen in the cathode active material. , ultimately avoiding fire and explosion caused by the continuous gas production of the non-aqueous electrolyte, thereby improving the safety performance and cycle performance of lithium-ion batteries under high temperature conditions.
  • Example 1 The test results obtained in Example 1 and Examples 15 to 19 are filled in Table 4.
  • Example 1 It can be seen from the test results of Example 1 and Examples 15 to 19 that for different compounds represented by structural formula 1, the mass percentage content a of Co in the positive electrode material layer, the specific surface area b of the positive electrode active material and the structural formula in the non-aqueous electrolyte
  • the mass percentage content c of the compound shown in 1 satisfies the condition 0.01 ⁇ 10c/(a*b) ⁇ 9, it plays a similar role, and both have a good improvement effect on the problem of insufficient thermal stability of lithium-ion batteries.
  • Example 1 (3) The test results obtained in Example 1 and Examples 20 to 23 are filled in Table 5.

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Abstract

一种锂离子电池，包括正极、负极和非水电解液，所述的正极包括正极集流体以及设置于所述正极集流体上的正极材料层，所述的正极材料层包括含有钴酸锂的正极活性材料，所述正极的热失效温度T 0＞220℃，所述的非水电解液包括非水有机溶剂、锂盐和添加剂。该锂离子电池具有较好的热箱安全性能和循环性能。

Description

一种锂离子电池 技术领域
本发明属于储能装置技术领域，具体涉及一种锂离子电池。
背景技术
锂离子电池是继镍氢等传统蓄电池之后的新一代可充电电池，由日本索尼公司于1990年最先研发成功。锂离子电池工作原理简单，具有较好的安全性和较长的充放电寿命，工作电压高，能量密度高，加上体积小，循环使用寿命长，工作温度范围宽等优点收到广泛应用。
随着新能源汽车对续航里程的不断提高和3C数码产品轻薄化的不断发展，电池行业越来越要求锂离子电池高能量密度化。设计高能量密度的锂离子电池可以从以下几个方面着手：1)提高正极材料克容量；2)提高电池放电平台；3)提电池中活性材料的比例；等等。提升锂离子电池的充电的截止电压是增大电池能量密度的重要途径之一，因为随着充电截止电压的提高，正极材料可以实现更高的克容量发挥，且放电平台有明显提高，两方面的作用对能量密度的提升具有立竿见影的效果。
钴酸锂(LCO)是目前高电压电池采用的正极材料，随着电池电压的逐渐提高，正极材料进入更高的脱锂态，材料结构稳定性会变差，且表面的氧化性也明显提高。随着高克容量正极材料的发展，材料结构的不稳定性及其高氧化性在极片/非水电解液界面表现地尤其明显，其中钴酸锂中的Co元素对于催化非水电解液的分解具有重要影响，具体表现为：电池发生产气，内阻快速增长，容量急剧下降。更重要的是会导致电池的安全性能下降，在进行电池热箱测试安全时，电池发生爆炸、燃烧等危险情况，因此需要匹配安全性能更好的非水电解液。
目前的材料发展趋势下，随着钴酸锂高电压趋势日益发展，高电压钴酸锂的安全性能问题逐渐加剧。为了改善这些问题，对电池材料进行保护是重要的手段之一，目前从非水电解液角度改善电池安全有两种，一种是选择高闪点的溶剂或高盐非水电解液，提高非水电解液本征安全稳定性，在进行热箱测试时延缓电压降时间，延缓电池燃烧爆炸时间。另一种是选择阻燃添加剂，提升非水电解液阻燃效果，从而抑制非水电解液燃烧改善安全性能。但这两种方法都对全电池的常规性能循环，存储性能产生大幅度劣化，无法有效兼顾常规性能与安全性能。
发明内容
针对现有钴酸锂电池存在无法兼顾安全性能和循环性能的问题，本发明提供了一种锂离子电池。
本发明解决上述技术问题所采用的技术方案如下：
本发明提供了一种锂离子电池，包括正极、负极和非水电解液，所述正极包括正极集流体以及设置于所述正极集流体上的正极材料层，所述正极材料层包括含有钴酸锂的正极活性材料，所述正极的热失效温度T0＞220℃，所述非水电解液包括非水有机溶剂、锂盐和添加剂，所述添加剂包括结构式1所示的化合物：

其中，n为0或1，A选自C或O，X选自R1、R2各自独立选自H、R1和R2不同时选自H，且X、R1和R2中至少含有一个硫原子；
所述锂离子电池满足以下条件：
0.01≤10c/(a*b)≤9，且57≤a≤60，0.1≤b≤0.8，0.01≤c≤5.5；
其中，a为正极材料层中Co的质量百分比含量，单位为％；
b为正极活性材料的比表面积，单位为m2/g；
c为非水电解液中结构式1所示的化合物的质量百分比含量，单位为％。
可选的，所述锂离子电池满足以下条件：
0.25≤10c/(a*b)≤2.5。
可选的，所述正极活性材料的比表面积b为0.15～0.5m2/g。
可选的，所述非水电解液中结构式1所示的化合物的质量百分比含量c为0.5～2.5％。
可选的，所述锂离子电池的充电电压≥4.48V。
可选的，所述结构式1所示的化合物选自以下化合物中的一种或多种：


可选的，所述非水有机溶剂包括碳酸乙烯酯、碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯、碳酸丙烯酯、乙酸丁酯、γ-丁内酯、丙酸丙酯、丙酸乙酯、丁酸乙酯、乙酸甲酯、乙酸乙酯、氟代乙酸乙酯和氟醚中的至少一种。
可选的，所述锂盐包括LiPF6、LiBOB、LiDFOB、LiPO2F2、LiBF4、LiSbF6、LiAsF6、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2、LiClO4、LiAlCl4、LiCF3SO3、Li2B10Cl10、LiSO3F、LiTOP、LiDODFP、LiOTF和低级脂肪族羧酸锂盐中的至少一种。
可选的，所述添加剂还包括环状硫酸酯类化合物、磺酸内酯类化合物、环状碳酸酯类化合物、磷酸酯类化合物、硼酸酯类化合物和腈类化合物中的至少一种；
以所述非水电解液的总质量为100％计，所述添加剂的含量为0.01％～30％。
可选的，所述环状硫酸酯类化合物选自硫酸乙烯酯、硫酸丙烯酯、甲基硫酸乙烯酯、中的至少一种；
所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,3-丙烯磺酸内酯中 的至少一种；
所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、亚甲基碳酸乙烯酯、氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯或结构式2所示化合物中的至少一种，
所述结构式2中，R21、R22、R23、R24、R25、R26各自独立地选自氢原子、卤素原子、C1-C5基团中的一种；
所述磷酸酯类化合物选自三(三甲基硅烷)磷酸酯、三(三甲基硅烷)亚磷酸酯或结构式3所示化合物中的至少一种：
所述结构式3中，R31、R32、R33各自独立的选自C1-C5的饱和烃基、不饱和烃基、卤代烃基、-Si(CmH2m+1)3，m为1～3的自然数，且R31、R32、R33中至少有一个为不饱和烃基；
所述硼酸酯类化合物选自三(三甲基硅烷)硼酸酯和三(三乙基硅烷)硼酸酯中的至少一种；
所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的至少一种。
根据本发明提供的锂离子电池，采用钴酸锂作为正极活性材料，使锂离子电池具有较高的能量密度，在非水电解液中添加结构式1所示的化合物，结构式1所示的化合物能够在正极材料层的表面成膜，对正极活性材料中的Co元素具有锚定作用，能够将Co元素锚定在正极活性材料的晶体结构中，以避免Co元素对于非水电解液在正极材料层的界面上的催化分解作用，发明人通过大量研究发现，正极材料层中Co的质量百分比含量a影响对于非水电解液的催化分解作用，而通过控制非水电解液中结构式1所示的化合物的质量百分比含量c和正极活性材料的比表面积b能够控制结构式1所示的化合物在正极材料层上的成膜质量，三者共同作用以影响锂离子电池在高温条件下的安全性和循环性能，当正极材料层中Co的质量百分比含量a、正极活性材料的比表面积b和非水电解液中结构式1所示的化合物的质量 百分比含量c满足条件0.01≤10c/(a*b)≤9，且57≤a≤60，0.1≤b≤0.8，0.01≤c≤5.5时，三者能够达到较好的配合效果，能够有效抑制Co催化非水电解液发生副反应，进一步抑制正极活性材料中晶格氧的迁移越位，最终避免了非水电解液持续产气诱发起火爆炸，有效提升了热箱安全性能和循环性能。
具体实施方式
为了使本发明所解决的技术问题、技术方案及有益效果更加清楚明白，以下结合实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
本发明提供了一种锂离子电池，包括正极、负极和非水电解液，所述正极包括正极集流体以及设置于所述正极集流体上的正极材料层，所述正极材料层包括含有钴酸锂的正极活性材料，所述正极的热失效温度T0＞220℃，所述非水电解液包括非水有机溶剂、锂盐和添加剂，所述添加剂包括结构式1所示的化合物：
其中，n为0或1，A选自C或O，X选自R1、R2各自独立选自H、R1和R2不同时选自H，且X、R1和R2中至少含有一个硫原子；
所述锂离子电池满足以下条件：
0.01≤10c/(a*b)≤9，且57≤a≤60，0.1≤b≤0.8，0.01≤c≤5.5；
其中，a为正极材料层中Co的质量百分比含量，单位为％；
b为正极活性材料的比表面积，单位为m2/g；
c为非水电解液中结构式1所示的化合物的质量百分比含量，单位为％。
所述锂离子电池采用钴酸锂作为正极活性材料，使锂离子电池具有较高的能量密度，在非水电解液中添加结构式1所示的化合物，结构式1所示的化合物能够在正极材料层的表面成膜，对正极活性材料中的Co元素具有锚定作用，能够将Co元素锚定在正极活性材料的晶体结构中，以避免Co元素对于非水电解液在正极材料层的界面上的催化分解作用，发明人通过大量研究发现，当正极材料层中Co的质量百分比含量a影响对于非水电解液的催化分解作用，而通过控制非水电解液中结构式1所示的化合物的质量百分比含量c和正极活性材料的比表面积b能够控制结构式1所示的化合物在正极材料层上的成膜质量，三者共同作用以影响锂离子电池在高温条件下的安全性和循环性能，当正极材料层中Co的质量百分比含量a、正极活性材料的比表面积b和非水电解液中结构式1所示的化合物的质量百分比含量c满足 条件0.01≤10c/(a*b)≤9，且57≤a≤60，0.1≤b≤0.8，0.01≤c≤5.5时，三者能够达到较好的配合效果，能够有效抑制Co催化非水电解液发生副反应，进一步抑制正极活性材料中晶格氧的迁移越位，最终避免了非水电解液持续产气诱发起火爆炸，有效提升了热箱安全性能和循环性能。
在优选的实施例中，所述锂离子电池满足以下条件：
0.25≤10c/(a*b)≤2.5。
通过上述关系式的限定，能够进一步综合正极材料层中Co的质量百分比含量a、正极活性材料的比表面积b和非水电解液中结构式1所示的化合物的质量百分比含量c对于电池性能的影响，提高锂离子电池的安全性能和循环性能。
在具体的实施例中，所述正极材料层中Co的质量百分比含量a可以为57％、57.3％、57.5％、57.8％、58％、58.3％、58.5％、58.8％、59％、59.3％、59.5％、59.8％或60％。
所述正极材料层中Co的质量百分含量a与正极材料层中含有的钴酸锂相关，随着正极材料层中Co的质量百分含量a的提高，所述正极的能量密度随之提升，同时，正极材料层表面的Co元素含量提升，非水电解液的副反应加剧，对应地，可通过控制正极活性材料的比表面积b和水非水电解液中结构式1所示的化合物的质量百分比含量c对非水电解液的副反应进行调控，在本发明的关系式0.01≤10c/(a*b)≤9限制条件下，通过将所述正极材料层中Co的质量百分含量a限制在上述范围中，有利于提高电池能量密度，并综合比表面积、结构式1所示的化合物含量等对非水电解液副反应进行抑制。
在具体的实施例中，所述正极活性材料的比表面积b可以为0.1m2/g、0.12m2/g、0.15m2/g、0.18m2/g、0.1m2/g、0.2m2/g、0.4m2/g、0.5m2/g、0.6m2/g、0.7m2/g或0.8m2/g。
在优选的实施例中，所述正极活性材料的比表面积b为0.15～0.5m2/g。
锂离子的脱嵌反应主要集中在正极材料层/非水电解液界面上进行，正极活性材料的比表面积越大，在相同的表观体积和有机非水电解液能够充分润湿的前提下，电极/非水电解液界面也就越大，锂离子的脱嵌速度也就越快，正极的离子传导能力越高，但是比表面积增大也容易导致正极材料层的结构强度不足，导致材料脱落的问题，也加剧了非水电解液的分解，同时，所述正极活性材料的比表面积b也直接影响单位质量的结构式1所示的化合物对于正极材料层表面的成膜厚度，与非水电解液中结构式1所示的化合物含量相互关联。
在具体的实施例中，所述非水电解液中结构式1所示的化合物的质量百分比含量c可以为0.01％、0.02％、0.05％、0.08％、0.1％、0.2％、0.4％、0.5％、0.7％、0.9％、1.0％、1.1％、1.3％、1.5％、1.8％、2.0％、2.3％、2.7％、3.0％、3.3％、3.7％、4.0％、4.3％、4.7％、5.0％或5.5％。
在优选的实施例中，所述非水电解液中结构式1所示的化合物的质量百分比含量c为0.5～2.5％。
若所述非水电解液中结构式1所示的化合物的质量百分比含量过低，则不利于在正极材料层表面形成一种稳定的界面膜，使得正极活性材料出现Co离子溶出问题，Co离子溶出促使正极材料相变加剧，内部应力积累，导致材料的非晶化和结构坍塌破裂，进而导致电池容量衰减；若所述非水电解液中结构式1所示的化合物的质量百分比含量过高，则会导致形成的界面膜过厚，增大电池的阻抗，因此当所述非水电解液中结构式1所示的化合物的质量百分比含量处于上述范围中时，有利于在正极材料层表面形成一种高离子电导率且稳定的界面膜，促进锂离子的扩散，同时有效锚定正极活性材料中的Co元素，改善电池的循环性能。
在一些实施例中，所述锂离子电池的充电电压≥4.48V。
在一些实施例中，所述结构式1所示的化合物选自以下化合物中的一种或多种：


需要说明的是，以上仅是本发明优选的化合物，并不代表对于本发明的限制。
本领域技术人员在知晓结构式1所示的化合物的结构式的情况下，根据化学合成领域的公知常识可以知晓上述化合物的制备方法。例如：化合物7可通过以下方法制成：
将山梨醇、碳酸二甲酯、甲醇碱性物质催化剂氢氧化钾以及DMF等有机溶剂置于反应容器中，在加热条件下进行反应数小时后，加入一定量的草酸调节pH至中性，过滤、重结晶后即可得到中间产物1，接着将中间产物1、碳酸酯、二氯亚砜等在高温条件下发生酯化反应得到中间产物2，再使用高碘酸钠等氧化剂将中间产物2氧化即可得到化合物7。
在一些实施例中，所述锂离子电池为软包电池或硬壳电池。
在一些实施例中，所述正极材料层还包括有正极粘结剂，所述正极粘结剂包括聚偏氟乙烯、偏氟乙烯的共聚物、聚四氟乙烯、偏氟乙烯-六氟丙烯的共聚物、四氟乙烯-六氟丙烯的共聚物、四氟乙烯-全氟烷基乙烯基醚的共聚物、乙烯-四氟乙烯的共聚物、偏氟乙烯-四氟乙烯的共聚物、偏氟乙烯-三氟乙烯的共聚物、偏氟乙烯-三氯乙烯的共聚物、偏氟乙烯-氟代乙烯的共聚物、偏氟乙烯-六氟丙烯-四氟乙烯的共聚物、热塑性聚酰亚胺、聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯、聚甲基丙烯酸甲酯等热塑性树脂；丙烯酸类树脂；羟甲基纤维素钠；丁腈橡胶、聚丁橡胶、乙烯-丙烯橡胶、苯乙烯-丁二烯-苯乙烯嵌段共聚物或其氢化物、乙烯-丙烯-二烯三元共聚物、聚乙酸乙烯酯、间规-1,2-聚丁二烯、乙烯-乙烯乙酸酯中的一种或多种。
在一些实施例中，所述正极材料层还包括正极导电剂，所述正极导电剂包括导电炭黑、导电碳球、导电石墨、导电碳纤维、碳纳米管、石墨烯或还原氧化石墨烯中的一种或多种。
在一些实施例中，所述正极集流体选自可传导电子的金属材料，优选的，所述正极集流体包括Al、Ni、锡、铜、不锈钢的一种或多种，在更优选的实施例中，所述正极集流体选自铝箔。
在一些实施例中，所述负极包括负极材料层，所述负极材料层包括负极活性材料。
在优选实施例中，所述负极活性材料包括碳基负极、硅基负极、锡基负极、锂负极中的至少一种。其中碳基负极可包括石墨、硬碳、软碳、石墨烯、中间相碳微球等；硅基负极可包括硅材料、硅的氧化物、硅碳复合材料以及硅合金材料等；锡基负极可包括锡、锡碳、锡氧、锡金属化合物；锂负极可包括金属锂或锂合金。锂合金具体可以是锂硅合金、锂钠合金、锂钾合金、锂铝合金、锂锡合金和锂铟合金中的至少一种。
在一些实施例中，所述负极材料层还包括有负极粘结剂和负极导电剂，所述负极活性材料、所述负极粘结剂和所述负极导电剂共混得到所述负极材料层。
所述负极粘接剂和负极导电剂的可选择范围分别与所述正极粘结剂和正极导电剂相同，在此不再赘述。
在一些实施例中，所述负极还包括负极集流体，所述负极材料层形成于所述负极集流体的表面。
所述负极集流体选自可传导电子的金属材料，优选的，所述负极集流体包括Al、Ni、锡、铜、不锈钢的一种或多种，在更优选的实施例中，所述负极集流体选自铜箔。
在一些实施例中，所述锂盐包括LiPF6、LiBOB、LiDFOB、LiPO2F2、LiBF4、LiSbF6、LiAsF6、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2、LiClO4、LiAlCl4、LiCF3SO3、Li2B10Cl10、LiSO2F、LiTOP、LiDODFP、LiOTF和低级脂肪族羧酸锂盐中的至少一种。
在一些实施例中，所述非水电解液中，所述锂盐的浓度为0.1mol/L～8mol/L。在优选实施例中，所述非水电解液中，所述锂盐的浓度为0.5mol/L～2.5mol/L。具体的，所述非水电解液中，所述锂盐的浓度可以为0.5mol/L、1mol/L、1.5mol/L、2mol/L、2.5mol/L。
在一些实施例中，所述非水有机溶剂包括醚类溶剂、腈类溶剂、碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。
在一些实施例中，醚类溶剂包括环状醚或链状醚，优选为碳原子数3～10的链状醚及碳原子数3～6的环状醚，环状醚具体可以但不限于是1,3-二氧戊烷(DOL)、1,4-二氧惡烷(DX)、冠醚、四氢呋喃(THF)、2-甲基四氢呋喃(2-CH3-THF)，2-三氟甲基四氢呋喃(2-CF3-THF)中的一种或多种；所述链状醚具体可以但不限于是二甲氧基甲烷、二乙氧基甲烷、乙氧基甲氧基甲烷、乙二醇二正丙基醚、乙二醇二正丁基醚、二乙二醇二甲基醚。由于链状醚与锂离子的溶剂化能力高、可提高离子解离性，因此特别优选粘性低、可赋予高离子电导率的二甲氧基甲烷、二乙氧基甲烷、乙氧基甲氧基甲烷。醚类化合物可以单独使用一种，也可以以任意的组合及比率组合使用两种以上。醚类化合物的含量没有特殊限制，在不显著破坏本发明高压实锂离子电池效果的范围内是任意的，在非水溶剂体积比为100％中通常体积比为1％以上、优选体积比为2％以上、更优选体积比为3％以上，另外，通常体积比为30％以下、优选体积比为25％以下、更优选体积比为20％以下。在将两种以上醚类化合物组合使用的情况下，使醚类化合物的总量满足上述范围即可。醚类化合物的含量在上述的优选范围内时，易于确保由链状醚的锂离子离解度的提高和粘度降低所带来的离子电导率的改善效果。另外，负极活性材料为碳基材料的情况下，可抑制因链状醚与锂离子共同发生共嵌入的现象，因此能够使输入输出特性、充放电速率特性达到适当的范围。
在一些实施例中，腈类溶剂具体可以但不限于是乙腈、戊二腈、丙二腈中的一种或多种。
在一些实施例中，碳酸酯类溶剂包括环状碳酸酯或链状碳酸酯，环状碳酸酯具体可以但不限于是碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(GBL)、碳酸亚丁酯(BC)中的一种或多种；链状碳酸酯具体可以但不限于是碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)中的一种或多种。环状碳酸酯的含量没有特殊限制，在不显著破坏本发明锂离子电池效果的范围内是任意的，但在单独使用一种的情况下其含量的下限相对于非水电解液的溶剂总量来说，通常体积比为3％以上、优选体积比为5％以上。通过设定该范围，可避免由于非水电解液的介电常数降低而导致电导率降低，易于使非水电解质电池的大电流放电特性、相对于负极的稳定性、循环特性达到良好的范围。另外，上限通常体积比为90％以下、优选体积比为85％以下、更优选体积比为80％以下。通过设定该范围，可提高非水电解液的氧化/还原耐性，从而有助于提高高温保存时的稳定性。链状碳酸酯的含量没有特殊限定，相对于非水电解液的溶剂总量，通常为体积比为15％以上、优选体积比为20％以上、更优选体积比为25％以上。另外，通常体积比为90％以下、优选体积比为85％以下、更优选体积比为80％以下。通过使链状碳酸酯的含量在上述范围，容易使非水电解液的粘度达到适当范围，抑制离子电导率的降低，进而有助于使非水电解质电池的输出 特性达到良好的范围。在组合使用两种以上链状碳酸酯的情况下，使链状碳酸酯的总量满足上述范围即可。
在一些实施例中，还可优选使用具有氟原子的链状碳酸酯类(以下简称为“氟化链状碳酸酯”)。氟化链状碳酸酯所具有的氟原子的个数只要为1以上则没有特殊限制，但通常为6以下、优选4以下。氟化链状碳酸酯具有多个氟原子的情况下，这些氟原子相互可以键合于同一个碳上，也可以键合于不同的碳上。作为氟化链状碳酸酯，可列举，氟化碳酸二甲酯衍生物、氟化碳酸甲乙酯衍生物、氟化碳酸二乙酯衍生物等。
羧酸酯类溶剂包括环状羧酸酯和/或链状碳酸酯。作为环状羧酸酯的例子，可以列举如：γ-丁内酯、γ-戊内酯、δ-戊内酯中的一种或多种。作为链状碳酸酯的例子，可以列举如：乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(EP)、乙酸丁酯、丙酸丙酯(PP)、丙酸丁酯中的一种或多种。
在一些实施例中，砜类溶剂包括环状砜和链状砜，优选地，在为环状砜的情况下，通常为碳原子数3～6、优选碳原子数3～5，在为链状砜的情况下，通常为碳原子数2～6、优选碳原子数2～5的化合物。砜类溶剂的含量没有特殊限制，在不显著破坏本发明锂离子电池效果的范围内是任意的，相对于非水电解液的溶剂总量，通常体积比为0.3％以上、优选体积比为0.5％以上、更优选体积比为1％以上，另外，通常体积比为40％以下、优选体积比为35％以下、更优选体积比为30％以下。在组合使用两种以上砜类溶剂的情况下，使砜类溶剂的总量满足上述范围即可。砜类溶剂的含量在上述范围内时，倾向于获得高温保存稳定性优异的非水电解液。
在优选的实施例终，所述非水有机溶剂包括碳酸乙烯酯、碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯、碳酸丙烯酯、乙酸丁酯、γ-丁内酯、丙酸丙酯、丙酸乙酯、丁酸乙酯、乙酸甲酯、乙酸乙酯、氟代乙酸乙酯和氟醚中的至少一种。
在优选的实施例中，所述非水有机溶剂为环状碳酸酯和链状碳酸酯的混合物。
在一些实施例中，所述添加剂还包括环状硫酸酯类化合物、磺酸内酯类化合物、环状碳酸酯类化合物、磷酸酯类化合物、硼酸酯类化合物和腈类化合物中的至少一种；
优选的，以所述非水电解液的总质量为100％计，所述添加剂的含量为0.01％～30％。
在一些实施例中，所述环状硫酸酯类化合物选自硫酸乙烯酯、硫酸丙烯酯、甲基硫酸乙烯酯、中的至少一种；
所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,3-丙烯磺酸内酯中的至少一种；
所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、亚甲基碳酸乙烯酯、氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯或结构式2所示化合物中的至少一种，
所述结构式2中，R21、R22、R23、R24、R25、R26各自独立地选自氢原子、卤素原子、C1-C5基团中的一种；
所述磷酸酯类化合物选自三(三甲基硅烷)磷酸酯、三(三甲基硅烷)亚磷酸酯或结构式3所示化合物中的至少一种：
所述结构式3中，R31、R32、R33各自独立的选自C1-C5的饱和烃基、不饱和烃基、卤代烃基、-Si(CmH2m+1)3，m为1～3的自然数，且R31、R32、R33中至少有一个为不饱和烃基；
在优选的实施例中，所述结构式3所示的磷酸酯类化合物可为磷酸三炔丙酯、二炔丙基甲基磷酸酯、二炔丙基乙基磷酸酯、二炔丙基丙基磷酸酯、二炔丙基三氟甲基磷酸酯、二炔丙基-2,2,2-三氟乙基磷酸酯、二炔丙基-3,3,3-三氟丙基磷酸酯、二炔丙基六氟异丙基磷酸酯、磷酸三烯丙酯、二烯丙基甲基磷酸酯、二烯丙基乙基磷酸酯、二烯丙基丙基磷酸酯、二烯丙基三氟甲基磷酸酯、二烯丙基-2,2,2-三氟乙基磷酸酯、二烯丙基-3,3,3-三氟丙基磷酸酯、二烯丙基六氟异丙基磷酸酯中的至少一种；
所述硼酸酯类化合物选自三(三甲基硅烷)硼酸酯和三(三乙基硅烷)硼酸酯中的至少一种；
所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的至少一种。
在另一些实施例中，所述添加剂还可包括其它能改善电池性能的添加剂：例如，提升电池安全性能的添加剂，具体如氟代磷酸酯、环磷腈等阻燃添加剂，或叔戊基苯、叔丁基苯等防过充添加剂。
需要说明的是，除非特殊说明，一般情况下，所述添加剂中任意一种可选物质在非水电解液中的含量为10％以下，优选的，含量为0.1-5％，更优选的，含量为0.1％～2％。具体的，所述添加剂中任意一种可选物质的含量可以为0.05％、0.08％、0.1％、0.5％、0.8％、1％、1.2％、1.5％、1.8％、2％、2.2％、2.5％、2.8％、3％、3.2％、3.5％、3.8％、4％、4.5％、5％、5.5％、 6％、6.5％、7％、7.5％、7.8％、8％、8.5％、9％、9.5％、10％。
在一些实施例中，当添加剂选自氟代碳酸乙烯酯时，以所述非水电解液的总质量为100％计，所述氟代碳酸乙烯酯的含量为0.05％～30％。
在一些实施例中，所述锂离子电池中还包括有隔膜，所述隔膜位于所述正极和所述负极之间。
所述隔膜可为现有常规隔膜，可以是陶瓷隔膜、聚合物隔膜、无纺布、无机-有机复合隔膜等，所述聚合物隔膜选自聚烯烃类、聚酰胺类、聚砜类、聚磷腈类、聚醚砜类、聚醚醚酮类、聚醚酰胺类和聚丙烯腈类中的一种或几种，包括但不限于单层PP(聚丙烯)、单层PE(聚乙烯)、双层PP/PE、双层PP/PP和三层PP/PE/PP等隔膜。
在优选的实施例，所述隔膜包括基材隔膜和表面涂层，表面涂层为无机颗粒或有机凝胶或二者混合物且涂覆在基材隔膜至少一侧表面。
以下通过实施例对本发明进行进一步的说明。
以下实施例和对比例涉及的化合物如下表所示：
表1
表2实施例和对比例各参数设计

实施例1
本实施例用于说明本发明公开的锂离子电池的制备方法，包括以下操作步骤：
1)非水电解液的制备
将碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸甲乙酯(EMC)按质量比为EC:DEC:EMC＝1:1:1进行混合，然后加入六氟磷酸锂(LiPF6)至摩尔浓度为1mol/L，再加入化合物7(注：此处化合物7即为表2中的化合物7，以下实施例类同)，化合物7在非水电解液中的含量按非水电解液的总质量计为0.5％。
2)正极板的制备
混合正极活性材料锂钴氧化物LiCoO2，导电碳黑Super-P和粘结剂聚偏二氟乙烯(PVDF)，然后将它们分散在N-甲基-2-吡咯烷酮(NMP)中，得到正极浆料。将浆料均匀涂布在铝箔的两面上，经过烘干、压延和真空干燥，并用超声波焊机焊上铝制引出线后得到正极板，极板的厚度在120-150μm，其中，正极材料层中Co的质量百分含量和正极活性材料LiCoO2的比表面积如表2所示。
3)负极板的制备
按94:1:2.5:2.5的质量比混合负极活性材料人造石墨，导电碳黑Super-P，粘结剂丁苯橡胶(SBR)和羧甲基纤维素(CMC)，然后将它们分散在去离子水中，得到负极浆料。将浆料涂布在铜箔的两面上，经过烘干、压延和真空干燥，并用超声波焊机焊上镍制引出线后得到负极板，极板的厚度在120-150μm。
4)电芯的制备
在正极板和负极板之间放置厚度为20μm的三层隔离膜，然后将正极板、负极板和隔膜组成的三明治结构进行卷绕，再将卷绕体压扁后放入铝箔包装袋，在75℃下真空烘烤48h，得到待注液的电芯。
5)电芯的注液和化成
在露点控制在-40℃以下的手套箱中，将上述制备的非水电解液注入电芯中，经真空封装，静止24h。
然后按以下步骤进行首次充电的常规化成：0.05C恒流充电180min,0.2C恒流充电至3.95V，二次真空封口，然后进一步以0.2C的电流恒流充电至4.48V后，以0.2C的电流恒流放电至3.0V。
实施例2～23
实施例2～23用于说明本发明公开的锂离子电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
采用表2中实施例2～23所示的添加剂及含量、正极材料层比表面积、正极材料层中Co的质量百分含量。
对比例1～11
对比例1～11用于对比说明本发明公开的锂离子电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
采用表2中对比例1～11所示的添加剂及含量、正极材料层比表面积、正极材料层中Co的质量百分含量。
性能测试
对上述制备得到的锂离子电池进行如下性能测试：
高温循环性能测试
将电池置于恒温45℃的烘箱中，以1C的电流恒流充电至4.48V然后恒压充电至电流下降至0.03C，然后以1C的电流恒流放电至3.0V，如此循环，记录第1圈的放电容量和最后一圈的放电容量，按下式计算高温循环的容量保持率和阻抗增长率：
容量保持率％＝最后一圈的放电容量/第1圈的放电容量*100％
阻抗增长率％＝(最后一圈的阻抗-第1圈的阻抗)/第1圈的阻抗*100％
安全性能测试
正极的热失效温度T0测试：非水电解液加入电池并化成后，0.2C恒流恒压充电至4.48V，截止电流0.03C；手套箱中，解剖电池，分离正负极片，用剪刀裁剪正极片；用DMC润洗正极片，待正极片干燥，装入坩埚，并滴加5微升非水电解液，移出手套箱，等待测试。测试条件：25-150℃:5℃/min；150-350℃:2.5℃/min，氮气气氛，测试正极的热失效温度T0。
热箱安全性能测试：电池按照前述的化成条件进行化成，化成后的电池以0.5C的电流恒流充电至4.48V然后恒压充电至电流下降至0.03C，然后以0.5C的电流恒流放电至3.0V，以此程序将电池常温25℃循环5圈，计算电池放电容量，放电容量偏差在±10mAh/g，则电池以0.5C的电流恒流充电至4.48V然后恒压充电至电流下降至0.03C，以此作为电池的满电状态。将满电电池放置在GX-3020-BL40热冲击试验箱中，热箱按照设定程序“以5℃/min从25℃升温至130℃在保持30min”进行工作，同时“数据采集仪”面板温度通道和电压通道开始记录实时数据。在测试过程中数据采集仪检测的电池表面温度不超过200℃，电压降不超过0.3V，同时电池不爆炸，不起火，则热箱通过OK，否则为NG。
(1)实施例1～14和对比例1～11得到的测试结果填入表3。
表3

由实施例1～13和对比例1～11的测试结果可知，在钴酸锂电池的非水电解液中加入结构式1所示的化合物，通过控制正极材料层中Co的质量百分比含量a、正极活性材料的比表面积b和非水电解液中结构式1所示的化合物的质量百分比含量c满足条件0.01≤10c/(a*b)≤9时，所得到的锂离子电池具有较好的安全性能，避免在高温条件下的热失控问题，同时，也具有更好的高温循环性能，说明通过控制非水电解液中结构式1所示的化合物的质量百分比含量c和正极活性材料的比表面积b能够控制结构式1所示的化合物在正极材料层上的成膜质量和厚度，同时正极材料层表面的界面膜的厚度与正极材料层中Co的质量百分比含量a具有相关性，当含有更高含量的Co时，其催化性更强，需要厚度更候的界面膜进行Co元素的锚定，三者共同作用抑制Co催化非水电解液发生副反应，进一步抑制正极活性材料中晶格氧的迁移越位，最终避免了非水电解液持续产气诱发起火爆炸，以提高锂离子电池在高温条件下的安全性能和循环性能。
由实施例1～13的测试结果可知，进一步的，当正极材料层中Co的质量百分比含量a、正极活性材料的比表面积b和非水电解液中结构式1所示的化合物的质量百分比含量c满足0.25≤10c/(a*b)≤2.5的限定，有利于进一步提升锂离子电池的热箱安全性以及循环性能，推测是由于通过10c/(a*b)值的进一步限定，有利于提高正极材料层表面界面膜的热稳定性，进而提高正极的热失效温度T0，改善锂离子电池在高温条件下的表现。
由对比例1～6的测试结果可知，即使正极材料层中Co的质量百分比含量a、正极活性材料的比表面积b和非水电解液中结构式1所示的化合物的质量百分比含量c满足条件0.01≤10c/(a*b)≤9的限定，但a值、b值或c值不满足其范围限定时，锂离子电池仍然不具有较好的高温表现，说明a值、b值或c值在提升锂离子电池高温性能上具有明显的关联，同样的，由对比例7～10的测试结果可知，当a值、b值和c值满足其范围限定，但c/(a*b)值不满足上述限定条件时，对于电池的高温稳定性提升不明显。
(2)实施例1、实施例15～19得到的测试结果填入表4。
表4

由实施例1、实施例15～19的测试结果可知，对于不同的结构式1所示的化合物，正极材料层中Co的质量百分比含量a、正极活性材料的比表面积b和非水电解液中结构式1所示的化合物的质量百分比含量c满足条件0.01≤10c/(a*b)≤9时，其起到的作用相似，均对于锂离子电池的热稳定性不足的问题具有较好的改善作用，有效提高了正极的热失效温度T0，提高了电池的高温循环下的容量保持率，同时降低了高温循环下的阻抗增率，说明本发明提供的关系式适用于不同的结构式1所示的化合物。
(3)实施例1、实施例20～23得到的测试结果填入表5。
表5
由实施例1、实施例20～23的测试结果可知，在本发明提供的电池体系中，额外加入氟代碳酸乙烯酯(FEC)、1,3-丙烷磺酸内酯(PS)、硫酸乙烯酯(DTD)或1,3,6-己烷三腈(HTCN)，能够进一步提高锂离子电池的高温循环容量保持率以及降低锂离子电池的阻抗增长率，说明其它添加剂对电池性能的提升机理与结构式1所示的化合物存在一定的差异，两者在成膜上存在互补作用，进而提高了正极材料层表面的界面膜的质量。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。

Claims (16)

  1. 一种锂离子电池，其特征在于，包括正极、负极和非水电解液，所述正极包括正极集流体以及设置于所述正极集流体上的正极材料层，所述正极材料层包括含有钴酸锂的正极活性材料，所述正极的热失效温度T0＞220℃，所述非水电解液包括非水有机溶剂、锂盐和添加剂，所述添加剂包括结构式1所示的化合物：
    其中，n为0或1，A选自C或O，X选自R1、R2各自独立选自H、R1和R2不同时选自H，且X、R1和R2中至少含有一个硫原子；
    所述锂离子电池满足以下条件：
    0.01≤10c/(a*b)≤9，且57≤a≤60，0.1≤b≤0.8，0.01≤c≤5.5；
    其中，a为正极材料层中Co的质量百分比含量，单位为％；
    b为正极活性材料的比表面积，单位为m2/g；
    c为非水电解液中结构式1所示的化合物的质量百分比含量，单位为％。
  2. 根据权利要求1所述的锂离子电池，其特征在于，所述锂离子电池满足以下条件：
    0.25≤10c/(a*b)≤2.5。
  3. 根据权利要求1所述的锂离子电池，其特征在于，所述正极活性材料的比表面积b为0.15～0.5m2/g。
  4. 根据权利要求1所述的锂离子电池，其特征在于，所述非水电解液中结构式1所示的化合物的质量百分比含量c为0.5～2.5％。
  5. 根据权利要求1所述的锂离子电池，其特征在于，所述锂离子电池的充电截止电压≥4.48V。
  6. 根据权利要求1所述的锂离子电池，其特征在于，所述结构式1所示的化合物选自以下化合物中的一种或多种：



  7. 根据权利要求1所述的锂离子电池，其特征在于，所述非水有机溶剂包括碳酸乙烯酯、碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯、碳酸丙烯酯、乙酸丁酯、γ-丁内酯、丙酸丙酯、丙酸乙酯、丁酸乙酯、乙酸甲酯、乙酸乙酯、氟代乙酸乙酯和氟醚中的至少一种。
  8. 根据权利要求1所述的锂离子电池，其特征在于，所述锂盐包括LiPF6、LiBOB、LiDFOB、LiPO2F2、LiBF4、LiSbF6、LiAsF6、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2、LiClO4、LiAlCl4、LiCF3SO3、Li2B10Cl10、LiSO3F、LiTOP、LiDODFP、LiOTF和低级脂肪族羧酸锂盐中的至少一种。
  9. 根据权利要求1所述的锂离子电池，其特征在于，所述添加剂还包括环状硫酸酯类化合物、磺酸内酯类化合物、环状碳酸酯类化合物、磷酸酯类化合物、硼酸酯类化合物和腈类化合物中的至少一种。
  10. 根据权利要求9所述的锂离子电池，其特征在于，以所述非水电解液的总质量为100％计，所述添加剂的含量为0.01％～30％。
  11. 根据权利要求9所述的锂离子电池，其特征在于，所述环状硫酸酯类化合物选自硫酸乙烯酯、硫酸丙烯酯、甲基硫酸乙烯酯、中的至少一种。
  12. 根据权利要求9所述的锂离子电池，其特征在于，所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,3-丙烯磺酸内酯中的至少一种。
  13. 根据权利要求9所述的锂离子电池，其特征在于，所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、亚甲基碳酸乙烯酯、氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯或结构式2所示化合物中的至少一种，
    所述结构式2中，R21、R22、R23、R24、R25、R26各自独立地选自氢原子、卤素原子、C1-C5基团中的一种。
  14. 根据权利要求9所述的锂离子电池，其特征在于，所述磷酸酯类化合物选自三(三甲基硅烷)磷酸酯、三(三甲基硅烷)亚磷酸酯或结构式3所示化合物中的至少一种：
    所述结构式3中，R31、R32、R33各自独立的选自C1-C5的饱和烃基、不饱和烃基、卤代烃基、-Si(CmH2m+1)3，m为1～3的自然数，且R31、R32、R33中至少有一个为不饱和烃基。
  15. 根据权利要求9所述的锂离子电池，其特征在于，所述硼酸酯类化合物选自三(三甲基硅烷)硼酸酯和三(三乙基硅烷)硼酸酯中的至少一种。
  16. 根据权利要求9所述的锂离子电池，其特征在于，所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的至少一种。
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