WO2020216060A1 - 电解液、锂离子电池及含有该锂离子电池的装置 - Google Patents

电解液、锂离子电池及含有该锂离子电池的装置 Download PDF

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WO2020216060A1
WO2020216060A1 PCT/CN2020/083610 CN2020083610W WO2020216060A1 WO 2020216060 A1 WO2020216060 A1 WO 2020216060A1 CN 2020083610 W CN2020083610 W CN 2020083610W WO 2020216060 A1 WO2020216060 A1 WO 2020216060A1
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electrolyte
silane
sulfur
ion battery
tris
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PCT/CN2020/083610
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English (en)
French (fr)
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陈培培
付成华
姜彬
梁成都
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宁德时代新能源科技股份有限公司
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Priority to EP20794605.4A priority Critical patent/EP3951986B1/en
Publication of WO2020216060A1 publication Critical patent/WO2020216060A1/zh
Priority to US17/511,379 priority patent/US20220045362A1/en

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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
    • H01M10/052—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
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • 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
    • H01M2300/0088—Composites
    • H01M2300/0091—Composites in the form of mixtures
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • 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

  • This application relates to the field of battery technology, and in particular to an electrolyte, a lithium ion battery, and a device containing the lithium ion battery.
  • Lithium-ion batteries are widely used in electric vehicles and consumer electronic products due to their advantages of high energy density, high output power, long cycle life and low environmental pollution.
  • lithium-ion batteries as power sources are required to have the characteristics of low impedance, long cycle life, long storage life, and excellent safety performance.
  • the lower impedance is conducive to ensuring good acceleration performance and dynamic performance.
  • Long storage life and long cycle life can make lithium-ion batteries have long-term reliability and maintain good performance during the normal use cycle of hybrid vehicles.
  • the purpose of this application is to provide an electrolyte, a lithium ion battery, and a device containing the lithium ion battery, the lithium ion battery can have both good high temperature cycle performance and low temperature discharge performance.
  • an electrolyte which includes a lithium salt, an organic solvent and an additive.
  • the additives include sulfur-containing compounds and silane compounds, and the sulfur-containing compounds are selected from one of sulfur hexafluoride, sulfuryl fluoride, sulfur dioxide, sulfur trioxide, carbon disulfide, dimethyl sulfide, and methyl ethyl sulfide.
  • a lithium ion battery which includes a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • the positive electrode piece includes a positive electrode current collector and a positive electrode film that is arranged on at least one surface of the positive electrode current collector and includes a positive electrode active material;
  • the negative electrode piece includes a negative electrode current collector and is arranged on at least one surface of the negative electrode current collector and includes The anode membrane of the anode active material;
  • the electrolyte is the electrolyte described in one aspect of the application.
  • a device including the lithium ion battery described in the second aspect of the present application.
  • This application uses a specific sulfur-containing compound and a silane compound as an additive to the electrolyte.
  • the sulfur-containing compound can not only form an SEI film on the surface of the negative electrode of a lithium ion battery, effectively prevent the direct contact between the electrolyte and the negative active material, but also optimize
  • the passivation film formed by the silane compound on the surface of the positive electrode reduces the film formation resistance on the surface of the positive electrode.
  • lithium-ion batteries can have both good high-temperature cycle performance and low-temperature discharge performance.
  • the device of the present application includes the lithium ion battery provided in the present application, and therefore has at least the same advantages as the lithium ion battery.
  • FIG. 1 is a schematic diagram of an embodiment of a lithium ion battery.
  • Figure 2 is an exploded view of Figure 1.
  • Fig. 3 is a schematic diagram of an embodiment of a battery module.
  • Fig. 4 is a schematic diagram of an embodiment of a battery pack.
  • Fig. 5 is an exploded view of Fig. 4.
  • Fig. 6 is a schematic diagram of an embodiment of a device in which a lithium ion battery is used as a power source.
  • the electrolyte of the first aspect of the application includes lithium salt, organic solvent and additives.
  • the additives include sulfur-containing compounds and silane compounds, and the sulfur-containing compounds are selected from sulfur hexafluoride (SF 6 ), sulfuryl fluoride (SO 2 F 2 ), sulfur dioxide (SO 2 ), and sulfur trioxide (SO 3 ) , One or more of carbon disulfide (CS 2 ), dimethyl sulfide (CH 2 SCH 3 ) and methyl ethyl sulfide.
  • the lithium salt and organic solvent in the electrolyte will undergo a reduction reaction on the surface of the negative electrode active material, and the reaction product is deposited on the surface of the negative electrode to form a dense solid electrolyte interface (SEI) film.
  • SEI dense solid electrolyte interface
  • the SEI film is insoluble in organic solvents and can exist stably in the electrolyte, and organic solvent molecules cannot pass through, which can effectively prevent the co-intercalation of solvent molecules and avoid the damage to the negative electrode active material caused by the co-intercalation of solvent molecules. Improve the cycle performance and service life of lithium-ion batteries.
  • the surface of the lithium-containing positive electrode active material is usually covered with a Li 2 CO 3 film. Therefore, when it comes into contact with the electrolyte, whether it is storage or charge-discharge cycle , The electrolyte can oxidize on the surface of the positive electrode, and the product of oxidation decomposition will be deposited on the surface of the positive electrode to replace the original Li 2 CO 3 film to form a new passivation film. The formation of the new passivation film will not only increase the positive electrode active material
  • the irreversible capacity of the lithium ion battery reduces the charging and discharging efficiency of the lithium ion battery. To a certain extent, it also hinders the extraction and insertion of lithium ions in the positive electrode active material, thereby reducing the cycle performance and charge and discharge performance of the lithium ion battery.
  • silane compounds can form a film on the surface of the positive electrode membrane of lithium-ion batteries to improve the high-temperature cycle performance of lithium-ion batteries, but its film-forming resistance is relatively high, which is not conducive to the low temperature of lithium-ion batteries Performance improvement.
  • the sulfur-containing compound can form a passivation film on both the positive and negative surfaces of lithium-ion batteries.
  • the passivation film also called solid electrolyte interface film, SEI film
  • SEI film solid electrolyte interface film
  • the sulfur-containing compound can form an SEI film on the surface of the negative electrode, thereby effectively preventing the direct contact between the electrolyte and the negative electrode active material; on the other hand, the sulfur-containing compound can also optimize the silane compound
  • the passivation film formed on the surface of the positive electrode can work together to make the passivation film formed on the surface of the positive electrode contain Si-O-SO 2 -components, which can effectively reduce the film formation resistance of the positive electrode surface and further improve the lithium ion battery Low-temperature discharge performance; at the same time, the force between the molecules of the specific sulfur-containing compound is small, and it can effectively reduce the viscosity of the electrolyte after being dissolved in the electrolyte, which can effectively prevent the solidification of the electrolyte at low temperatures, and can improve the low-temperature discharge performance of the battery Improve further.
  • the electrolyte of the present application includes specific sulfur-containing compounds and silane compounds at the same time, and the lithium ion battery can take into account both good high-temperature cycle performance and low-temperature discharge performance.
  • the sulfur-containing compound may be selected from one or more of sulfur hexafluoride (SF 6 ), sulfuryl fluoride (SO 2 F 2 ), sulfur dioxide (SO 2 ), and sulfur trioxide (SO 3 ) .
  • SF 6 sulfur hexafluoride
  • SO 2 F 2 sulfuryl fluoride
  • SO 2 sulfur dioxide
  • SO 3 sulfur trioxide
  • the silane compound is selected from one or more of the compounds represented by Formula 1, Formula 2 and Formula 3; wherein, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 31 , R 32 , R 33 , R 34 , R 35 , R 36 , R 37 , R 38 , and R 39 are each independently selected from one or more of C1-C6 alkyl groups or C1-C6 haloalkyl groups.
  • the silane compound may be selected from tris(trimethyl)silane phosphate, tris(trimethyl)silane phosphite, tris(trimethyl) Silane borate, tris(triethyl)silane phosphate, tris(triethyl)silane phosphite, tris(triethyl)silane borate, tris(trifluoromethyl)silane phosphate, tris( Trifluoromethyl)silane phosphite, tris(trifluoromethyl)silane borate, tris(2,2,2-trifluoroethyl)silane phosphate, tris(2,2,2-trifluoroethane) Base) silane phosphite, tris(2,2,2-trifluoroethyl)silane borate, tris(hexafluoroisopropyl)silane phosphate,
  • the sulfur-containing compound can participate in the formation of a passivation film on the surface of the positive electrode of the lithium ion battery, and can also participate in the formation of the SEI film on the surface of the negative electrode of the lithium ion battery, if sulfur contains The content of the compound is too low, it is difficult to cooperate with the silane compound to form a complete passivation film on the surface of the positive electrode, and it is difficult to form a complete SEI film on the surface of the negative electrode, so it cannot effectively prevent the direct contact of the electrolyte with the positive and negative active materials.
  • the mass of the sulfur-containing compound is 0.1% to 8% of the total mass of the electrolyte.
  • the mass of the sulfur-containing compound is 0.5% to 5% of the total mass of the electrolyte.
  • the content of the silane compound is too low, the formation of a passivation film on the surface of the positive electrode is difficult to effectively prevent the direct contact between the electrolyte and the positive electrode active material.
  • the high-temperature cycle performance of the lithium ion battery is unfavorable; if the content of the silane compound is too high, too much silane compound will accumulate on the surface of the positive and negative electrodes, increasing the film formation resistance on the surface of the positive and negative electrodes, thereby deteriorating the performance of the lithium ion battery.
  • the mass of the silane compound is 0.1% to 5% of the total mass of the electrolyte.
  • the mass of the silane compound is 0.1% to 3% of the total mass of the electrolyte.
  • the mass ratio of the two in the electrolyte can be matched reasonably, so that the two can give full play to their While their respective functions can take into account the synergy, it will not only further improve the low-temperature discharge performance and high-temperature cycle performance of the lithium-ion battery, but also reduce the cost.
  • the mass content of the sulfur-containing compound in the electrolyte is greater than the mass content of the silane compound.
  • the type of the lithium salt is not particularly limited, and can be selected according to actual needs.
  • the lithium salt may be selected from LiN (C x F 2x+1 SO 2 ) (C y F 2y+1 SO 2 ), LiPF 6 , LiBF 4 , LiBOB, LiAsF 6 , Li(CF 3 SO 2 ) 2 One or more of N, LiCF 3 SO 3 and LiClO 4 , where x and y are natural numbers.
  • the type of the organic solvent is not particularly limited, and can be selected according to actual needs.
  • the organic solvent may be selected from propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, vinylene carbonate, fluorocarbon Ethylene carbonate, methyl formate, ethyl acetate, ethyl propionate, propyl propionate, methyl butyrate, methyl acrylate, vinyl sulfite, propylene sulfite, dimethyl sulfite, diethyl Sulfite, 1,3-propane sultone, vinyl sulfate, acid anhydride, N-methylpyrrolidone, N-methylformamide, N-methylacetamide, acetonitrile, N,N-dimethylformamide One or more of amide,
  • the lithium ion battery of the second aspect of the present application includes a positive pole piece, a negative pole piece, a separator and an electrolyte.
  • the positive electrode piece includes a positive electrode current collector and a positive electrode film that is arranged on at least one surface of the positive electrode current collector and includes a positive electrode active material
  • the negative electrode piece includes a negative electrode current collector and is arranged on at least one surface of the negative electrode current collector and includes Negative membrane of negative active material.
  • the electrolyte is the electrolyte described in the first aspect of the application.
  • the positive electrode active material is selected from materials capable of extracting and inserting lithium ions.
  • the positive electrode active material can be selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and the above-mentioned compounds plus others One or more of compounds derived from transition metals or non-transition metals, but the application is not limited to these materials.
  • the negative electrode active material is selected from materials capable of inserting and extracting lithium ions.
  • the negative electrode active material can be selected from one or more of carbon materials, silicon-based materials, tin-based materials, and lithium titanate, but the present application is not limited to these materials.
  • the carbon material can be selected from one or more of graphite, soft carbon, hard carbon, carbon fiber, and mesophase carbon microspheres;
  • the graphite can be selected from one or more of artificial graphite and natural graphite
  • the silicon-based material may preferably be selected from one or more of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, and silicon alloys;
  • the tin-based material may preferably be selected from elemental tin, tin oxide compounds, tin alloys One or more of them.
  • the type of the isolation film is not specifically limited, and can be selected according to actual needs.
  • the isolation film may be polyethylene, polypropylene, polyvinylidene fluoride and their multilayer composite film, but is not limited to these.
  • Fig. 1 shows a lithium-ion battery 5 with a square structure as an example.
  • the lithium-ion battery may include an outer package for packaging the positive pole piece, the negative pole piece, the separator, and the electrolyte.
  • the outer packaging of the lithium ion battery may be a soft bag, such as a pouch type soft bag.
  • the material of the soft bag can be plastic, for example, it can include one or more of polypropylene PP, polybutylene terephthalate PBT, polybutylene succinate PBS, and the like.
  • the outer packaging of the lithium ion battery can also be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, and the like.
  • the outer package may include a housing 51 and a cover 53.
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the housing 51 has an opening communicating with the containing cavity, and a cover plate 53 can cover the opening to close the containing cavity.
  • the positive pole piece, the negative pole piece and the separator may be laminated or wound to form a laminated structure electrode assembly or a wound structure electrode assembly 52.
  • the electrode assembly 52 is packaged in the receiving cavity.
  • the electrolyte is infiltrated in the electrode assembly 52.
  • the number of electrode assemblies 52 contained in the lithium ion battery 5 can be one or several, which can be adjusted according to requirements.
  • lithium ion batteries can be assembled into battery modules, and the number of lithium ion batteries contained in the battery modules can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of lithium ion batteries 5 may be arranged in order along the length direction of the battery module 4. Of course, it can also be arranged in any other manner. Furthermore, the plurality of lithium ion batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having an accommodation space, and a plurality of lithium ion batteries 5 are accommodated in the accommodation space.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3.
  • the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4.
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • a third aspect of the present application provides a device including the lithium ion battery described in the second aspect of the present application.
  • the lithium ion battery can be used as a power source of the device, and can also be used as an energy storage unit of the device.
  • the device can be, but is not limited to, mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf Vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select a lithium ion battery, battery module or battery pack according to its usage requirements.
  • Figure 6 is a device as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or battery module can be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, etc.
  • the device is usually thin and light, and sodium ion batteries can be used as a power source.
  • the lithium ion batteries of Examples 1-20 and Comparative Examples 1-3 were prepared according to the following methods.
  • the positive electrode active material LiNi 0.5 Mn 0.3 Co 0.2 O 2 , the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are dissolved in the solvent N-methylpyrrolidone (NMP) in a weight ratio of 94:3:3 ,
  • NMP N-methylpyrrolidone
  • the positive electrode slurry is obtained after fully stirring and mixing uniformly; then the positive electrode slurry is uniformly coated on the positive electrode current collector aluminum (Al) foil, and then the positive electrode pole piece is obtained through drying, cold pressing and slitting.
  • the negative active material artificial graphite, conductive agent acetylene black, binder styrene butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC) are dissolved in a solvent to deionize in a weight ratio of 95:2:2:1
  • the negative electrode slurry is obtained after fully stirring and mixing uniformly; then the negative electrode slurry is uniformly coated on the negative electrode current collector copper (Cu) foil, and then dried, cold pressed, and slit to obtain the negative electrode pole piece.
  • Cu negative electrode current collector copper
  • Polyethylene (PE) porous polymer film is used as the separator.
  • the positive pole piece, the isolation film, and the negative pole piece are stacked in order, so that the isolation film is located between the positive pole piece and the negative pole piece for isolation, and is wound to obtain an electrode assembly. Place the electrode assembly in the outer package, inject the prepared electrolyte and package it.
  • the discharge capacity at this time is the discharge capacity of the lithium-ion battery in the first cycle.
  • the lithium-ion battery is subjected to the 500-cycle charge-discharge test in the above manner, and the discharge capacity of the 500th cycle is detected.
  • Capacity retention rate of 500 cycles of lithium ion battery at 45°C (%) (discharge capacity of the 500th cycle/discharge capacity of the first cycle) ⁇ 100%
  • Examples 1-20 of the present application can simultaneously add specific types of sulfur-containing compounds and silane compounds to the electrolyte, so that lithium-ion batteries can be considered simultaneously Good high temperature cycle performance and low temperature discharge performance.
  • Comparative Example 1 neither a sulfur compound nor a silane compound was added, and the high-temperature cycle performance and low-temperature discharge performance of the lithium ion battery were both poor.
  • Comparative Example 2 only SO 2 was added, and in Comparative Example 3 only tris(trimethyl)silane phosphate was added.
  • the high temperature cycle performance and low temperature discharge performance of the lithium ion battery have been improved to a certain extent, the degree of improvement is It is still difficult to meet actual usage requirements.
  • Example 9 The content of SO 2 in Example 9 is too high, and excessive SO 2 oxidation and decomposition products will accumulate on the surface of the positive electrode, which will increase the impedance of the passivation film formed on the surface of the positive electrode, which is unfavorable for improving the high temperature cycle performance of the lithium ion battery.
  • Example 6 and Examples 10-16 From the analysis of the test results of Example 6 and Examples 10-16, it can be seen that the content of the silane compound in Example 10 is too low, and it cannot form a complete passivation film on the surface of the positive electrode. Therefore, it is not enough to prevent the electrolyte and the positive electrode active material from mixing. Further contact is not conducive to improving the high temperature cycle performance of lithium ion batteries.
  • the content of the silane compound in Example 6 and Examples 11-15 is moderate, and the lithium ion battery has both good high-temperature cycle performance and low-temperature discharge performance.
  • the content of the silane compound in Example 16 is too high. Too much silane compound will accumulate on the surface of the positive and negative electrodes and increase the film formation resistance of the positive and negative electrodes, which is disadvantageous to the performance improvement of the lithium ion battery.

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Abstract

本申请提供了一种电解液、锂离子电池及含有该锂离子电池的装置。所述电解液包括锂盐、有机溶剂以及添加剂。所述添加剂包括含硫化合物以及硅烷化合物，所述含硫化合物选自六氟化硫、硫酰氟、二氧化硫、三氧化硫，二硫化碳、二甲硫醚以及甲基乙基硫醚的一种或几种。当特定的含硫化合物与硅烷化合物共同作为电解液的添加剂使用时，含硫化合物既可以参与在锂离子电池的负极表面形成SEI膜，有效阻止电解液与负极活性材料的直接接触，又可以优化硅烷化合物在正极表面形成的钝化膜，降低正极表面的成膜阻抗。在两者的协同作用下，锂离子电池可兼顾较好的高温循环性能和低温放电性能。

Description

电解液、锂离子电池及含有该锂离子电池的装置
本申请要求于2019年4月26日提交中国专利局、申请号为201910344676.5、申请名称为“电解液及锂离子电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电池技术领域，尤其涉及一种电解液、锂离子电池及含有该锂离子电池的装置。
背景技术
锂离子电池由于具备能量密度大、输出功率高、循环寿命长和环境污染小等优点而被广泛应用于电动汽车以及消费类电子产品中。对于电动汽车的的应用来说，其要求作为动力电源的锂离子电池具有阻抗低、循环寿命长、存储寿命长及安全性能优异等特点。较低的阻抗有利于保障良好的加速性能以及动力学性能，当其应用于混合动力车时，其可以更大程度的回收能量、提高燃油效率，同时还可以提高混合动力车的充电速率。长的存储寿命和长的循环寿命可以使锂离子电池具有长期的可靠性，在混合动力车正常使用周期内保持良好的性能。
电解液与正、负极的相互作用对锂离子电池的性能具有较大的影响。因此为满足混合动力车对动力电源的需求，有必要提供一种具有良好的综合性能的电解液及锂离子电池。
发明内容
鉴于背景技术中存在的问题，本申请的目的在于提供一种电解液、锂离子电池及含有该锂离子电池的装置，所述锂离子电池可以同时兼顾较好的高温循环性能和低温放电性能。
为了达到上述目的，在本申请的第一方面，提供了一种电解液，其包括锂盐、有机溶剂以及添加剂。所述添加剂包括含硫化合物以及硅烷化合物， 所述含硫化合物选自六氟化硫、硫酰氟、二氧化硫、三氧化硫，二硫化碳、二甲硫醚以及甲基乙基硫醚的一种或几种。
在本申请的第二方面，提供了一种锂离子电池，其包括正极极片、负极极片、隔离膜以及电解液。所述正极极片包括正极集流体以及设置在正极集流体至少一个表面上且包括正极活性材料的正极膜片；所述负极极片包括负极集流体以及设置在负极集流体至少一个表面上且包括负极活性材料的负极膜片；所述电解液为本申请一方面所述的电解液。
在本申请的第三方面，提供了一种装置，其包括本申请第二方面所述的锂离子电池。
本申请至少包括如下所述的有益效果：
本申请将特定的含硫化合物与硅烷化合物共同作为电解液的添加剂使用，含硫化合物既可以在锂离子电池的负极表面形成SEI膜，有效阻止电解液与负极活性材料的直接接触，又可以优化硅烷化合物在正极表面形成的钝化膜，降低正极表面的成膜阻抗。在两者的协同作用下，锂离子电池可兼顾较好的高温循环性能和低温放电性能。本申请的装置包括本申请提供的锂离子电池，因而至少具有与所述锂离子电池相同的优势。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是锂离子电池的一实施方式的示意图。
图2是图1的分解图。
图3是电池模块的一实施方式的示意图。
图4是电池包的一实施方式的示意图。
图5是图4的分解图。
图6是锂离子电池用作电源的装置的一实施方式的示意图。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
下面详细说明本申请的电解液及锂离子电池。
首先说明本申请第一方面的电解液。
本申请第一方面的电解液包括锂盐、有机溶剂以及添加剂。所述添加剂包括含硫化合物以及硅烷化合物，所述含硫化合物选自六氟化硫(SF 6)、硫酰氟(SO 2F 2)、二氧化硫(SO 2)、三氧化硫(SO 3)，二硫化碳(CS 2)、二甲硫醚(CH 2SCH 3)以及甲基乙基硫醚的一种或几种。
对于锂离子电池的负极而言，在首次充放电的过程中，电解液中的锂盐和有机溶剂会在负极活性材料表面发生还原反应，反应产物沉积于负极表面形成一层致密的固态电解质界面(SEI)膜。SEI膜具有有机溶剂不溶性，在电解液中可以稳定存在，并且有机溶剂分子不能通过，从而能有效防止溶剂分子的共嵌入，避免了因溶剂分子共嵌入对负极活性材料造成的破坏，因而可以大大提高锂离子电池的循环性能和使用寿命。
而对于锂离子电池的正极而言，由于空气中CO 2的作用，含锂正极活性材料的表面通常覆盖有Li 2CO 3膜，因此当其与电解液接触后，无论是存储还是充放电循环，电解液均能在正极表面发生氧化反应，其氧化分解的产物会沉积于正极表面取代原来的Li 2CO 3膜形成新的钝化膜，新钝化膜的生成不仅会增大正极活性材料的不可逆容量，降低锂离子电池的充放电效率，在某种程度上其还会阻碍锂离子在正极活性材料中的脱出和嵌入，从而降低锂离子电池的循环性能和充放电性能。
在锂离子电池的充放电过程中，硅烷化合物可以在锂离子电池的正极膜片表面成膜，改善锂离子电池的高温循环性能，但其成膜阻抗相对较高，不利于锂离子电池的低温性能的改善。而含硫化合物则可在锂离子电池的正、负极表面均形成钝化膜，其在负极表面形成的钝化膜(又称为固态电解质界 面膜，SEI膜)可以阻止电解液与负极活性材料的直接接触，进而抑制电解液的还原反应。当硅烷化合物与含硫化合物同时使用时，一方面含硫化合物可以在负极表面形成的SEI膜，进而有效地阻止电解液与负极活性材料的直接接触，另一方面含硫化合物还可以优化硅烷化合物在正极表面形成的钝化膜，二者协同作用可以使正极表面形成的钝化膜中含有Si-O-SO 2-成分，从而可以有效降低正极表面的成膜阻抗，进一步改善锂离子电池的低温放电性能；同时，特定的含硫化合物分子间的作用力较小，其溶解于电解液后能够有效降低电解液的粘度，可以有效防止低温时电解液的凝固，能够对电池的低温放电性能进一步改善。
本申请的电解液中同时包括特定的含硫化合物以及硅烷化合物，锂离子电池可同时兼顾较好的高温循环性能和低温放电性能。
优选地，所述含硫化合物可选自六氟化硫(SF 6)、硫酰氟(SO 2F 2)、二氧化硫(SO 2)以及三氧化硫(SO 3)中的一种或几种。
在本申请第一方面所述的电解液中，所述硅烷化合物选自式1、式2以及式3所示的化合物中的一种或几种；其中，R 11、R 12、R 13、R 14、R 15、R 16、R 17、R 18、R 19、R 21、R 22、R 23、R 24、R 25、R 26、R 27、R 28、R 29、R 31、R 32、R 33、R 34、R 35、R 36、R 37、R 38、R 39各自独立地选自C1～C6的烷基或C1～C6的卤代烷基中的一种或几种。
Figure PCTCN2020083610-appb-000001
Figure PCTCN2020083610-appb-000002
在本申请第一方面所述的电解液中，具体地，所述硅烷化合物可选自三(三甲基)硅烷磷酸酯、三(三甲基)硅烷亚磷酸酯、三(三甲基)硅烷硼酸酯、三(三乙基)硅烷磷酸酯、三(三乙基)硅烷亚磷酸酯、三(三乙基)硅烷硼酸酯、三(三氟甲基)硅烷磷酸酯、三(三氟甲基)硅烷亚磷酸酯、三(三氟甲基)硅烷硼酸酯、三(2,2,2-三氟乙基)硅烷磷酸酯、三(2,2,2-三氟乙基)硅烷亚磷酸酯、三(2,2,2-三氟乙基)硅烷硼酸酯、三(六氟异丙基)硅烷磷酸酯、三(六氟异丙基)硅烷亚磷酸酯以及三(六氟异丙基)硅烷硼酸酯一种或几种。
在本申请第一方面所述的电解液中，由于含硫化合物既可以参与在锂离子电池的正极表面形成钝化膜，又可以参与在锂离子电池的负极表面形成SEI膜，因此若含硫化合物的含量过低，其难以与硅烷化合物协同以在正极表面形成完整的钝化膜，也难以在负极表面形成完整的SEI膜，因此无法有效地阻止电解液与正负极活性材料的直接接触；若含硫化合物的含量过高，则过量的含硫化合物氧化分解而产生的反应产物会堆积于正极表面，使正极表面形成的钝化膜的阻抗上升，从而会恶化锂离子电池的高温循环性能。
优选地，所述含硫化合物的质量为所述电解液总质量的0.1％～8％。
进一步优选地，所述含硫化合物的质量为所述电解液总质量的0.5％～5％。
在本申请第一方面所述的电解液中，若硅烷化合物的含量过低，则其在正极表面形成钝化膜难以有效地阻止电解液与正极活性材料的直接接触，因此对改善锂离子电池的高温循环性能不利；若硅烷化合物的含量过高，则过多的硅烷化合物会堆积在正负极表面，增大正负极表面的成膜阻抗，进而恶化锂离子电池的性能。
优选地，所述硅烷化合物的质量为所述电解液总质量的0.1％～5％。
进一步优选地，所述硅烷化合物的质量为所述电解液总质量的0.1％～3％。
在本申请第一方面所述的电解液中，由于含硫化合物和硅烷化合物共同 作为电解液的添加剂使用，因此合理匹配两者在电解液中的质量配比，可以使两者在充分发挥其各自作用的同时又能兼顾协同性，不仅有利于进一步的提升锂离子电池的低温放电性能和高温循环性能，同时还能降低成本。
优选地，电解液中含硫化合物的质量含量大于硅烷化合物的质量含量。
在本申请第一方面所述的电解液中，所述锂盐的种类没有特别的限制，可根据实际需求进行选择。具体地，所述锂盐可选自LiN(C xF 2x+1SO 2)(C yF 2y+1SO 2)、LiPF 6、LiBF 4、LiBOB、LiAsF 6、Li(CF 3SO 2) 2N、LiCF 3SO 3以及LiClO 4中的一种或几种，其中，x、y为自然数。
在本申请第一方面所述的电解液中，所述有机溶剂的种类没有特别的限制，可根据实际需求进行选择。具体地，所述有机溶剂可选自碳酸丙烯酯、碳酸乙烯酯、碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲乙酯、碳酸甲丙酯、碳酸亚乙烯酯、氟代碳酸乙烯酯、甲酸甲酯、乙酸乙酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丙烯酸甲酯、乙烯亚硫酸酯、丙烯亚硫酸酯、亚硫酸二甲酯、二乙基亚硫酸酯、1，3-丙磺酸内酯、硫酸乙烯酯、酸酐、N-甲基吡咯烷酮、N-甲基甲酰胺、N-甲基乙酰胺、乙腈、N,N-二甲基甲酰胺、环丁砜、二甲亚砜、甲硫醚、γ-丁内酯以及四氢呋喃中的一种或几种。
其次说明本申请第二方面的锂离子电池。
本申请第二方面的锂离子电池包括正极极片、负极极片、隔离膜以及电解液。所述正极极片包括正极集流体以及设置在正极集流体至少一个表面上且包括正极活性材料的正极膜片，所述负极极片包括负极集流体以及设置在负极集流体至少一个表面上且包括负极活性材料的负极膜片。所述电解液为本申请第一方面所述的电解液。在本申请第二方面所述的锂离子电池中，所述正极活性材料选自能够脱出和嵌入锂离子的材料。具体地，所述正极活性材料可选自锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物以及上述化合物添加其他过渡金属或非过渡金属得到的化合物中的一种或几种，但本申请并不限定于这些材料。
在本申请第二方面所述的锂离子电池中，所述负极活性材料选自能够嵌入和脱出锂离子的材料。具体地，所述负极活性材料可选自碳材料、硅基材料、锡基材料、钛酸锂中的一种或几种，但本申请并不限定于这些材料。其中，所述碳材料可选自石墨、软碳、硬碳、碳纤维、中间相碳微球中的一种 或几种；所述石墨可选自人造石墨、天然石墨中的一种或几种；所述硅基材料可优选选自单质硅、硅氧化合物、硅碳复合物、硅合金中的一种或几种；所述锡基材料可优选选自单质锡、锡氧化合物、锡合金中的一种或几种。
在本申请第二方面所述的锂离子电池中，所述隔离膜的种类没有具体的限制，可根据实际需求进行选择。例如，所述隔离膜可以是聚乙烯、聚丙烯、聚偏氟乙烯以及它们的多层复合膜，但不仅限于这些。
本申请对锂离子电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图1是作为一个示例的方形结构的锂离子电池5。
在一些实施例中，锂离子电池可包括外包装，用于封装正极极片、负极极片、隔离膜和电解液。
在一些实施例中，锂离子电池的外包装可以是软包，例如袋式软包。软包的材质可以是塑料，如可包括聚丙烯PP、聚对苯二甲酸丁二醇酯PBT、聚丁二酸丁二醇酯PBS等中的一种或几种。锂离子电池的外包装也可以是硬壳，例如硬塑料壳、铝壳、钢壳等。
在一些实施例中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。
正极极片、负极极片和隔离膜可经叠片或卷绕形成叠片结构电极组件或卷绕结构电极组件52。电极组件52封装于所述容纳腔。电解液浸润于电极组件52中。
锂离子电池5所含电极组件52的数量可以为一个或几个，可根据需求来调节。
在一些实施例中，锂离子电池可以组装成电池模块，电池模块所含锂离子电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个锂离子电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个锂离子电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个锂离子电池5容纳于该容纳空间。
在一些实施例中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
本申请的第三方面提供一种装置，所述装置包括本申请第二方面所述的锂离子电池。所述锂离子电池可以用作所述装置的电源，也可以作为所述装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
所述装置可根据其使用需求来选择锂离子电池、电池模块或电池包。
图6是作为一个示例的装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用钠离子电池作为电源。
下面结合实施例，进一步阐述本申请。应理解，这些实施例仅用于说明本申请而不用于限制本申请的范围。因为在本申请公开内容的范围内进行各种修改和变化对本领域技术人员来说是明显的。实施例中使用的所有试剂都可商购获得或是按照常规方法进行合成获得，并且可直接使用而无需进一步处理，以及实施例中使用的仪器均可商购获得。
实施例1-20和对比例1-3的锂离子电池均按照下述方法进行制备。
(1)正极极片的制备
将正极活性材料LiNi 0.5Mn 0.3Co 0.2O 2、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比为94:3:3溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后得到正极浆料；接着将正极浆料均匀涂覆于正极集流体铝(Al) 箔上，之后经过烘干、冷压、分切，得到正极极片。
(2)负极极片的制备
将负极活性材料人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按照重量比为95:2:2:1溶于溶剂去离子水中，充分搅拌混合均匀后得到负极浆料；接着将负极浆料均匀涂覆于负极集流体铜(Cu)箔上，之后经过烘干、冷压、分切，得到负极极片。
(3)电解液的制备
将碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)按照质量比为30:70混合，然后加入浓度为1M的锂盐LiPF 6，接着加入含硫化合物和硅烷化合物，搅拌均匀后，得到电解液，其中，含硫化合物的种类及含量，硅烷化合物的种类及含量的选择示出在表1中。
(4)隔离膜的制备
以聚乙烯(PE)多孔聚合薄膜作为隔离膜。
(5)锂离子电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片中间起到隔离作用，并卷绕得到电极组件。将电极组件置于外包装中，注入配好的电解液并封装。
接下来说明锂离子电池的测试过程。
(1)锂离子电池的低温放电性能测试
常温下，将锂离子电池以0.5C恒流充电至电压高于4.3V，然后进一步以4.3V恒压充电至电流低于0.05C，接着将锂离子电池以0.5C放电至3.0V，得到此时锂离子电池的放电容量并记为D0；之后将锂离子电池以0.5C恒流充电至电压高于4.3V，然后进一步以4.3V恒压充电至电流低于0.05C，接着将锂离子电池置于-10℃环境中，静置2h，之后将锂离子电池以0.5C放电至3.0V，得到此时锂离子电池的放电容量并记为D1。每组取5支锂离子电池进行测试，取平均值。
锂离子电池-10℃、0.5C的放电效率ε(％)＝D1/D0×100％
(2)锂离子电池的高温循环性能测试
在45℃下，将锂离子电池以0.7C(即2h内完全放掉理论容量的电流值)恒流恒压充电至上限电压为4.3V，然后以0.5恒流放电至电压为3V，此为一 个充放电循环过程，此时的放电容量为锂离子电池首次循环的放电容量，将锂离子电池按照上述方式进行500次循环充放电测试，检测得到第500次循环的放电容量。
锂离子电池45℃下循环500次的容量保持率(％)＝(第500次循环的放电容量/首次循环的放电容量)×100％
表1实施例1-20和对比例1-3的参数及性能测试结果
Figure PCTCN2020083610-appb-000003
Figure PCTCN2020083610-appb-000004
从表1的测试结果分析可知，与对比例1-3相比，本申请的实施例1-20通过在电解液中同时加入特定种类的含硫化合物和硅烷化合物，可以使锂离子电池同时兼顾良好的高温循环性能和低温放电性能。对比例1中既没有加入含硫化合物也没有加入硅烷化合物，锂离子电池的高温循环性能和低温放电性能均较差。对比例2中仅加入了SO 2，对比例3中仅加入了三(三甲基)硅烷磷酸酯，虽然锂离子电池的高温循环性能和低温放电性能得到了一定程度的改善，但是其改善程度仍然难以满足实际的使用需求。
从实施例1-9的测试结果分析可知，实施例1中的SO 2含量过低，其在正极表面形成的钝化膜以及在负极表面形成的SEI膜不足以有效地阻止电解液与正、负极活性材料的进一步反应，因此虽然锂离子电池的高温循环性能和低温放电性能可以得到改善，但改善效果并不明显。实施例2-8中的SO 2和硅烷化合物的含量均适中，锂离子电池可同时兼顾较好的高温循环性能和低温放电性能。实施例9中的SO 2的含量过高，过量的SO 2氧化分解的产物会堆积于正极表面，使正极表面形成的钝化膜的阻抗上升，从而对改善锂离子电池的高温循环性能不利。
从实施例6、实施例10-16的测试结果分析可知，实施例10中硅烷化合物的含量过低，其在正极表面无法形成完整的钝化膜，因此不足以阻止电解液与正极活性材料的进一步接触，因此不利于改善锂离子电池的高温循环性能。实施例6、实施例11-15中的硅烷化合物的含量适中，锂离子电池同时兼 顾较好的高温循环性能和低温放电性能。实施例16中的硅烷化合物的含量过高，过多的硅烷化合物会堆积在正负极表面、增大正负极表面的成膜阻抗，进而对锂离子电池的性能改善不利。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (13)

  1. 一种电解液，包括：
    锂盐；
    有机溶剂；以及
    添加剂；
    其中，
    所述添加剂包括含硫化合物以及硅烷化合物；
    所述含硫化合物选自六氟化硫、硫酰氟、二氧化硫、三氧化硫，二硫化碳、二甲硫醚以及甲基乙基硫醚的一种或几种。
  2. 根据权利要求1所述的电解液，其中，所述硅烷化合物选自式1、式2以及式3所示的化合物中的一种或几种
    Figure PCTCN2020083610-appb-100001
    其中，R 11、R 12、R 13、R 14、R 15、R 16、R 17、R 18、R 19、R 21、R 22、R 23、R 24、R 25、R 26、R 27、R 28、R 29、R 31、R 32、R 33、R 34、R 35、R 36、R 37、R 38、R 39各自独立地选自C1～C6的烷基或C1～C6的卤代烷基中的一种或几种。
  3. 根据权利要求1-2任一项所述的电解液，其中，所述硅烷化合物选自三(三甲基)硅烷磷酸酯、三(三甲基)硅烷亚磷酸酯、三(三甲基)硅烷硼酸酯、三(三乙基)硅烷磷酸酯、三(三乙基)硅烷亚磷酸酯、三(三乙基)硅烷硼酸酯、三(三氟甲基)硅烷磷酸酯、三(三氟甲基)硅烷亚磷酸酯、三(三氟甲基)硅烷硼酸酯、三(2,2,2-三氟乙基)硅烷磷酸酯、三(2,2,2-三氟乙基)硅烷亚磷酸酯、三(2,2,2-三氟乙基)硅烷硼酸酯、三(六氟异丙基)硅烷磷酸酯、三(六氟异丙基)硅烷亚磷酸酯以及三(六氟异丙基)硅烷硼酸酯一种或几种。
  4. 根据权利要求1-3任一项所述的电解液，其中，所述含硫化合物选自六氟化硫、硫酰氟、二氧化硫以及三氧化硫中的一种或几种。
  5. 根据权利要求1-4任一项所述的电解液，其中，所述含硫化合物的质量为所述电解液总质量的0.1％～8％。
  6. 根据权利要求5所述的电解液，其中，所述含硫化合物的质量为所述电解液总质量的0.5％～5％。
  7. 根据权利要求1-6任一项所述的电解液，其中，所述硅烷化合物的质量为所述电解液总质量的0.1％～5％。
  8. 根据权利要求7所述的电解液，其中，所述硅烷化合物的质量为所述电解液总质量的0.1％～3％。
  9. 根据权利要求1-8任一项所述的电解液，其中，所述电解液中含硫化合物的质量含量大于硅烷化合物的质量含量。
  10. 一种锂离子电池，包括：
    正极极片，包括正极集流体以及设置在正极集流体至少一个表面上且包括正极活性材料的正极膜片；
    负极极片，包括负极集流体以及设置在负极集流体至少一个表面上且包括负极活性材料的负极膜片；
    隔离膜；以及
    电解液；
    其中，所述电解液为权利要求1至9中任一项所述的电解液。
  11. 根据权利要求10所述的锂离子电池，其中，所述正极活性材料选自锂镍钴锰氧化物、锂镍钴铝氧化物以及上述化合物添加其他过渡金属或非过渡金属得到的化合物中的一种或几种。
  12. 根据权利要求10或11所述的锂离子电池，其中，所述负极活性材料选自碳材料、硅基材料中的一种或几种。
  13. 一种装置，其中，所述装置包括权利要求10-12任一项所述的锂离子电池。
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