WO2022218145A1 - 一种非水电解液及锂离子电池 - Google Patents

一种非水电解液及锂离子电池 Download PDF

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WO2022218145A1
WO2022218145A1 PCT/CN2022/083554 CN2022083554W WO2022218145A1 WO 2022218145 A1 WO2022218145 A1 WO 2022218145A1 CN 2022083554 W CN2022083554 W CN 2022083554W WO 2022218145 A1 WO2022218145 A1 WO 2022218145A1
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group
cyclic
structural formula
aqueous electrolyte
additive
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PCT/CN2022/083554
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English (en)
French (fr)
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胡时光
钱韫娴
黄雄
曹朝伟
向晓霞
邓永红
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深圳新宙邦科技股份有限公司
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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
    • 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
    • H01M10/056—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
    • H01M10/0568—Liquid materials characterised by the solutes
    • 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
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • 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 battery materials, and in particular relates to a non-aqueous electrolyte and a lithium ion battery.
  • Lithium-ion batteries are widely used in daily life and production due to their excellent performance. In recent years, with the development of consumer electronic products and new energy vehicles, the battery industry is increasingly demanding high energy density of lithium-ion batteries.
  • Designing high-energy-density lithium-ion batteries can start from the following aspects: 1. Improve the gram capacity of the positive electrode material; 2. Improve the battery discharge platform; 3. Improve the proportion of active materials in the battery, etc. Improving the charge cut-off voltage of lithium-ion batteries is one of the important ways to increase the energy density of the battery, because with the increase of the charge cut-off voltage, the positive electrode material can achieve higher gram capacity, and the discharge platform is significantly improved. The effect has an immediate effect on the increase in energy density.
  • the cathode material With the gradual increase of the battery voltage, the cathode material enters a higher delithiation state, the structural stability of the material will deteriorate, and the oxidization of the surface will also be significantly improved. With the development of high gram-capacity cathode materials, the instability of the material structure and its high oxidative properties are particularly evident at the electrode/electrolyte interface. The specific manifestations are: the battery produces gas, the internal resistance increases rapidly, and the capacity drops sharply. . The gas production of the battery will lead to an increase in the internal pressure, which may further develop into dangerous situations such as battery explosion and combustion.
  • the protection of battery materials is one of the important means.
  • a stable protective film can be formed on the surface of the positive electrode, avoiding side reactions between the electrolyte and the positive electrode material, and effectively controlling the battery development.
  • the phenomenon of producing gas, rapid increase in internal resistance, and sharp decline in capacity has found that although unsaturated phosphate or sulfate/sulfonate additives can control the gas production, internal resistance growth and capacity decline of batteries, they are still incapable of high temperature storage and high temperature cycle performance. To meet market needs, it is also necessary to further improve the high-temperature storage and high-temperature cycle performance of batteries.
  • the technical problem solved by the present invention is to solve the problem that the high-temperature storage and high-temperature cycle performance of existing lithium-ion batteries containing unsaturated phosphates or sulfates/sulfonates cannot meet the needs of the market, so as to provide a better High temperature cycling performance and high temperature storage performance of non-aqueous electrolytes and lithium-ion batteries.
  • the present invention provides a non-aqueous electrolyte solution, comprising a solvent, an electrolyte salt, a first additive and a second additive, the first additive being selected from at least one of the compounds shown in Structural Formula 1:
  • A, B and C are each independently selected from the group consisting of cyclic carbonate group, cyclic sulfate group, cyclic sulfite group, cyclic sulfonate group, cyclic sulfone group, cyclic sulfoxide group, a cyclic carboxylate group or a cyclic acid anhydride group;
  • D and E are each independently selected from a single bond, or a group containing a hydrocarbylene group, an ether bond, a sulfur-oxygen double bond or a carbon-oxygen double bond; the first The two additives are selected from at least one of the sulfate/sulfonic acid ester compounds shown in structural formula 2 and the phosphoric acid ester compounds shown in structural formula 3:
  • R 14 is selected from oxygen, F-containing C1-C5 alkylene, C1-C5 saturated alkylene or unsaturated hydrocarbylene
  • R 15 is selected from hydrogen atom, halogen atom or C1-C5 alkyl, n an integer selected from 0 to 3;
  • R 16 , R 17 and R 18 are each independently selected from C1-C5 saturated hydrocarbon group, unsaturated hydrocarbon group or halogenated hydrocarbon group, and at least one of R 16 , R 17 and R 18 is an unsaturated hydrocarbon group;
  • the total mass of the non-aqueous electrolyte is 100%, the addition amount of the first additive is 0.01-5.0%; the addition amount of the sulfate/sulfonic acid ester compound represented by the structural formula 2 is 0.01-5.0% ;
  • the addition amount of the phosphoric acid ester compound represented by the structural formula 3 is 0.01-1.0%.
  • A, B, and C independently contain a cyclic carbonate group, a cyclic sulfate group, a cyclic sulfite group, a cyclic sulfonate group, a cyclic sulfone group, and a cyclic sulfoxide group.
  • the number of cyclic carboxylate groups and cyclic acid anhydride groups is 1 to 5
  • A, B, and C contain cyclic carbonate groups, cyclic sulfate groups, cyclic sulfite groups, and cyclic sulfonic acid groups.
  • the total number of ester groups, cyclic sulfone groups, cyclic sulfoxide groups, cyclic carboxylic acid ester groups and cyclic acid anhydride groups is less than or equal to 10.
  • a and C are each independently selected from the groups shown in structural formula 4:
  • n is selected from an integer from 0 to 4
  • R 1 is selected from hydrogen, halogen, C1-C5 hydrocarbon group or halogenated hydrocarbon group
  • R 2 , R 3 , R 4 , R 5 , R 6 , R 7 are independently selected from each other From C1-C3 alkylene group, C1-C3 alkoxy group, oxygen atom
  • At least one of R 2 , R 3 and R 4 is selected from And at least one of R 2 , R 3 and R 4 is selected from oxygen atoms
  • at least one of R 5 , R 6 and R 7 is selected from And at least one of R 5 , R 6 and R 7 is selected from And at least one of R 5 , R 6 and R 7 is selected from oxygen atoms.
  • B is selected from the group shown in structural formula 5:
  • m is selected from an integer of 1 to 4
  • R 8 , R 9 and R 10 are each independently selected from C1-C3 hydrocarbylene, C1-C3 alkoxy, oxygen atom, At least one of R 8 , R 9 and R 10 is selected from And at least one of R 8 , R 9 and R 10 is selected from oxygen atoms.
  • D and E are each independently selected from the groups shown in structural formula 6:
  • z is selected from an integer from 0 to 4
  • R 11 and R 13 are each independently selected from a single bond or a C1-C5 hydrocarbylene group
  • R 12 is selected from a single bond
  • D and E are each independently selected from single bonds or C1-C5 alkylene groups
  • A, B, and C are each independently selected from substituted or unsubstituted cyclic carbonate groups, cyclic sulfate groups, cyclic sulfite group, cyclic sulfonate group, cyclic sulfone group, cyclic sulfoxide group, cyclic carboxylate group or cyclic acid anhydride group;
  • the substituent when A, B or C is substituted, is selected from halogen, hydrocarbyl or halogenated hydrocarbyl, more preferably, when A, B or C is substituted, the substituent is selected from halogen, alkyl or haloalkyl.
  • a and C are the same as each other, A and B are the same or different from each other, and D and E are the same as each other.
  • the sulfate/sulfonate compound shown in the structural formula 2 is selected from at least one of the following compounds:
  • the phosphoric acid ester compound shown in the structural formula 3 is selected from at least one of the following compounds:
  • the addition amount of the first additive is denoted as x
  • the addition amount of the sulfate/sulfonate compound shown in the structural formula 2 is denoted as x.
  • y the addition amount of the sulfate/sulfonate compound shown in the structural formula 2
  • the addition amount of the first additive is x
  • the addition amount of the phosphate compound represented by the structural formula 3 is z
  • the present invention also provides a lithium ion battery, comprising a positive electrode, a negative electrode and the above-mentioned non-aqueous electrolyte.
  • the compound represented by the structural formula 1 is added to the electrolyte, and the sulfate/sulfonic acid ester compound represented by the structural formula 2 or the phosphoric acid ester compound represented by the structural formula 3 is used together,
  • the additive of structural formula 1 takes precedence over the sulfate/sulfonic acid ester of structural formula 2 or the phosphate compound shown in structural formula 3 to form an SEI film on the negative electrode, passivate the surface of the negative electrode and inhibit the
  • the consumption of sulfate/sulfonate or phosphate shown in structural formula 3 at the negative electrode avoids side reactions between the electrolyte and the negative electrode, and at the same time makes more sulfate/sulfonate or phosphate compounds decompose on the surface of the positive electrode, stabilizing
  • the cathode material structure inhibits the dissolution of metal ions under high voltage, so as to achieve stable performance
  • An embodiment of the present invention provides a non-aqueous electrolyte solution, including a solvent, an electrolyte salt, a first additive and a second additive, wherein the first additive is selected from at least one of the compounds shown in Structural Formula 1:
  • A, B and C are each independently selected from the group consisting of cyclic carbonate group, cyclic sulfate group, cyclic sulfite group, cyclic sulfonate group, cyclic sulfone group, cyclic sulfoxide group, a cyclic carboxylate group or a cyclic acid anhydride group;
  • D and E are each independently selected from a single bond, or a group containing a hydrocarbylene group, an ether bond, a sulfur-oxygen double bond or a carbon-oxygen double bond; the first The two additives are selected from at least one of the sulfate/sulfonic acid ester compounds shown in structural formula 2 and the phosphoric acid ester compounds shown in structural formula 3:
  • R 14 is selected from oxygen, F-containing C1-C5 alkylene, C1-C5 saturated alkylene or unsaturated hydrocarbylene
  • R 15 is selected from hydrogen atom, halogen atom or C1-C5 alkyl, n an integer selected from 0 to 3;
  • R 16 , R 17 and R 18 are each independently selected from C1-C5 saturated hydrocarbon group, unsaturated hydrocarbon group or halogenated hydrocarbon group, and at least one of R 16 , R 17 and R 18 is an unsaturated hydrocarbon group;
  • the addition amount of the first additive is 0.01-5.0%; the addition amount of the sulfate/sulfonate compound represented by the structural formula 2 is 0.01-5.0% 5.0%;
  • the addition amount of the phosphoric acid ester compound represented by the structural formula 3 is 0.01-1.0%.
  • the compound represented by the structural formula 1 is added to the electrolyte, and the sulfate/sulfonic acid ester compound represented by the structural formula 2 or the phosphoric acid ester compound represented by the structural formula 3 is used together,
  • the additive of structural formula 1 takes precedence over the sulfate/sulfonic acid ester shown in structural formula 2 or the phosphate compound shown in structural formula 3 to form an SEI film on the negative electrode, passivate the surface of the negative electrode and inhibit structural formula 2.
  • the consumption of the shown sulfate/sulfonate or the phosphate shown in Structural Formula 3 at the negative electrode avoids side reactions between the electrolyte and the negative electrode, while making the sulfate/sulfonate shown in Structural Formula 2 or Structural Formula 3 shown in Phosphate ester compounds decompose more on the surface of the positive electrode, stabilize the structure of the positive electrode material, and inhibit the dissolution of metal ions under high voltage, so as to achieve stable performance during high-temperature cycling and high-temperature storage.
  • the inventors have found that when the addition amount of the sulfate/sulfonic acid ester compound shown in structural formula 2 is 0.01 to 5.0%, 0.01 to 5.0% of the first additive shown in structural formula 1 is added to the non-aqueous electrolyte. , the inventor speculates that the additive of structural formula 1 is preferentially reduced to the sulfate/sulfonic acid ester compound shown in structural formula 2 in the battery formation process, and a film is formed on the surface of the negative electrode to form an inner layer SEI, and then the sulfuric acid ester/sulfonic acid ester shown in structural formula 2 The sulfonate compounds are then reduced to form the outer SEI, and the decomposition products of the two include sulfur-containing organic and inorganic substances.
  • the short-chain organic product reduced by the sulfate/sulfonate compound shown in structure formula 2 and the product of the inner layer structure formula 1 will polymerize under the catalysis of specific substances to form long- and short-chain A-B-A long-chain products, and the inner and outer layers together form a more optimized SEI , which is conducive to ion transport and avoids side reactions between the electrolyte and the negative electrode.
  • the compound of structural formula 1 obviously inhibits the consumption of the sulfate/sulfonic acid ester compound shown in structural formula 2, so that the sulfate/sulfonic acid ester compound shown in structural formula 2 is more decomposed on the surface of the positive electrode, stabilizing the structure of the positive electrode material , inhibit the dissolution of metal ions under high voltage, so as to achieve stable performance during high temperature cycling and high temperature storage.
  • a passivation film can be formed at the positive electrode, and the passivation film can isolate the electrolyte from the high-voltage positive electrode interface. , thereby suppressing side reactions at the interface between the electrolyte and the positive electrode.
  • a film formation reaction easily occurs on the surface of the negative electrode, which significantly increases the negative electrode impedance.
  • the first additive shown in structural formula 1 it is speculated that the compound of structure 1 can form SEI in the negative electrode in preference to the phosphate compound shown in structural formula 3, and the surface of the negative electrode is passivated, thereby inhibiting the consumption of phosphate ester of the compound shown in structural formula 3 in the negative electrode, so that It reacts more at the positive electrode, which not only protects the positive electrode better, but also improves the high-temperature storage and high-temperature cycling performance of the battery.
  • A, B, and C each independently contain a cyclic carbonate group, a cyclic sulfate group, a cyclic sulfite group, a cyclic sulfonate group, a cyclic sulfone group, a cyclic sulfite group
  • the number of sulfone group, cyclic carboxylate group and cyclic acid anhydride group is 1 to 5, and A, B, C cyclic carbonate group, cyclic sulfate group, cyclic sulfite group, cyclic sulfonic acid group
  • the total number of ester groups, cyclic sulfone groups, cyclic sulfoxide groups, cyclic carboxylate groups and cyclic acid anhydride groups is less than or equal to 10.
  • a and C are each independently selected from groups represented by structural formula 4:
  • n is selected from an integer from 0 to 4
  • R 1 is selected from hydrogen, halogen, C1-C5 hydrocarbon group or halogenated hydrocarbon group
  • R 2 , R 3 , R 4 , R 5 , R 6 , R 7 are independently selected from each other From C1-C3 alkylene group, C1-C3 alkoxy group, oxygen atom
  • At least one of R 2 , R 3 and R 4 is selected from And at least one of R 2 , R 3 and R 4 is selected from oxygen atoms
  • at least one of R 5 , R 6 and R 7 is selected from And at least one of R 5 , R 6 and R 7 is selected from And at least one of R 5 , R 6 and R 7 is selected from oxygen atoms.
  • the combined group of -R 3 -R 2 -R 4 - and the combined group of -R 7 -R 5 -R 6 - are each independently selected from
  • B is selected from the group represented by Structural Formula 5:
  • m is selected from an integer of 1 to 4
  • R 8 , R 9 and R 10 are each independently selected from C1-C3 hydrocarbylene, C1-C3 alkoxy, oxygen atom, At least one of R 8 , R 9 and R 10 is selected from And at least one of R 8 , R 9 and R 10 is selected from oxygen atoms.
  • the combined groups of -R 9 -R 8 -R 10 - are each independently selected from
  • D and E are each independently selected from groups represented by structural formula 6:
  • z is selected from an integer from 0 to 4
  • R 11 and R 13 are each independently selected from a single bond or a C1-C5 hydrocarbylene group
  • R 12 is selected from a single bond
  • a and C are the same as each other, A and B are the same or different from each other, and D and E are the same as each other.
  • the compound represented by the structural formula 1 is a symmetrical structure, and the compound represented by the structural formula 1 of the symmetrical structure is easier to synthesize than the asymmetrical structure, The yield of the product is higher, which is beneficial to reduce the production cost.
  • D and E are each independently selected from single bonds or C1-C5 hydrocarbylene groups
  • A, B, and C are each independently selected from substituted or unsubstituted cyclic carbonate groups, cyclic sulfate groups , cyclic sulfite group, cyclic sulfonate group, cyclic sulfone group, cyclic sulfoxide group, cyclic carboxylate group or cyclic acid anhydride group.
  • the substituent when A, B or C is substituted, is selected from halogen, hydrocarbyl or halogenated hydrocarbyl, more preferably, when A, B or C is substituted, the substituent is selected from halogen, alkyl or haloalkyl.
  • the first additive may be selected from one or more of the following compounds:
  • D and E are each independently selected from groups represented by structural formula 6:
  • z is selected from an integer of 1-4
  • R 11 and R 13 are each independently selected from a single bond or a C1-C5 hydrocarbylene group
  • R 12 is selected from
  • A, B and C are each independently selected from substituted or unsubstituted cyclic carbonate groups, cyclic sulfate groups, cyclic sulfite groups, cyclic sulfonate groups, cyclic sulfone groups, cyclic sulfoxide groups group, cyclic carboxylate group or cyclic acid anhydride group, preferably, when A, B or C is substituted, the substituent is selected from halogen, hydrocarbon group or halogenated hydrocarbon group, more preferably, when A, B or C is substituted , the substituents are selected from halogen, alkyl or haloalkyl.
  • the first additive may be selected from one or more of the following compounds:
  • the first additive may also be selected from one or more of the following compounds:
  • Compound 1-1 can be prepared by the following methods:
  • the organic solvents such as sorbitol, dimethyl carbonate, methanol alkaline substance catalyst potassium hydroxide and DMF are placed in the reaction vessel, and after reacting for several hours under heating conditions, a certain amount of oxalic acid is added to adjust the pH to neutrality, and the solution is filtered. After recrystallization, intermediate product 1 can be obtained, and then intermediate product 1, carbonate, thionyl chloride, etc. are esterified under high temperature conditions to obtain intermediate product 2, and then intermediate product 2 is obtained by using an oxidant such as sodium periodate. Compound 1-1 can be obtained by oxidation.
  • the first additive is added in an amount of 0.01-5.0% based on 100% of the total mass of the non-aqueous electrolyte.
  • the additive amount may be 0.01%, 0.02%, 0.05%, 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%.
  • the sulfuric acid ester/sulfonic acid ester compound represented by the structural formula 2 is selected from at least one of the following compounds:
  • the sulfate/sulfonate compound represented by the structural formula 2 is used as a film-forming additive, has a low oxidation potential, is prone to oxidation reaction on the surface of the positive electrode material, and participates in the formation of a passivation film on the surface of the positive electrode material. It can effectively inhibit the oxidation reaction of the electrolyte solvent, and at the same time, it can also protect the positive electrode and inhibit the dissolution of transition metals in the positive electrode material.
  • the silicon-carbon bond in this type of compound is easily broken and combined with a trace amount of HF in the electrolyte to remove water and acid, and increase the content of organic components in the passivation film, increasing the toughness of the passivation film.
  • the sulfuric acid ester/sulfonic acid ester compound shown in structural formula 2 in this additive acts synergistically with the first additive shown in structural formula 1 to form a dense and stable SEI film on the surface of the negative electrode, effectively preventing the reduction reaction of the electrolyte on the surface of the negative electrode
  • the deposition with transition metals improves the interface between the anode and the electrolyte, and slows down the side reactions at the electrode interface during storage or cycling, thereby improving the high-temperature storage and high-temperature cycling performance of the battery.
  • the phosphate compound represented by the structural formula 3 is selected from at least one of the following compounds:
  • the phosphoric acid ester compound shown in the structural formula 3 is used as a positive electrode film-forming additive, and participates in the generation of a passivation film on the surface of the positive electrode material. It plays a positive role in protecting the positive electrode, and at the same time inhibits the dissolution of transition metals in the positive electrode material, improving the impedance growth and capacity loss of the battery.
  • the phosphoric acid ester shown in structural formula 3 in this additive and the first additive shown in structural formula 1 act synergistically to form a dense and stable SEI film on the surface of the negative electrode, which effectively prevents the reduction reaction of the electrolyte on the surface of the negative electrode and the deposition of transition metals. Improve the interface between the negative electrode and the electrolyte, slow down the side reaction of the electrode interface during storage or cycling, thereby improving the high-temperature storage and high-temperature cycling performance of the battery.
  • the addition amount of the first additive is x
  • the addition amount of the sulfate/sulfonic acid ester compound represented by the structural formula 2 is y, then these substances satisfy: 1% ⁇ y ⁇ 5%, and 0.01% ⁇ x ⁇ 1%; or 0.01% ⁇ y ⁇ 1%, and 1% ⁇ x ⁇ 5%.
  • the inventors have found through research that the combination of the compound represented by structural formula 1 and the sulfate/sulfonic acid ester compound represented by structural formula 2 can improve the high-temperature storage and high-temperature cycle performance of the battery, and the ratio between the two can improve the battery performance. It is very important that if the content of both is too low, it will not play a significant role in improving the performance of the battery. If the content of both is too high, it will cause increased gas production and affect the performance of the battery.
  • the total content of the compound represented by the structural formula 1 and the sulfate/sulfonic acid ester compound represented by the structural formula 2 must be limited within a certain range, when 1% ⁇ y ⁇ 5%, and 0.01% ⁇ x ⁇ 1% or 0.01% When % ⁇ y ⁇ 1%, and 1% ⁇ x ⁇ 5%, the battery system achieves the best high-temperature storage gas swelling and high-temperature cycle performance.
  • the addition amount of the first additive is x
  • the addition amount of the phosphoric acid ester compound represented by structural formula 3 is z, then these substances satisfy: 0.1% ⁇ x+z ⁇ 2% .
  • the compound of structural formula 1 and the phosphate compound of structural formula 3 can be used together to improve the high and low temperature storage and cycle performance of the battery, and the ratio between the two is very important to improve the performance of the battery, and the content of both is too low , it will not play a significant role in improving the performance of the battery. If the content of both is too high, it will cause an increase in gas production and affect the performance of the battery.
  • the inventors have found that when 0.1% ⁇ x+z ⁇ 2%, the negative SEI is mainly composed of the reduction product of structural formula 1, and the positive SEI is mainly composed of the oxidation product of the phosphate ester shown in structural formula 3. At this time, the battery It has lower inflation rate and better high temperature storage and cycle performance.
  • the non-aqueous electrolyte further includes a third additive selected from at least one of fluoroethylene carbonate, vinylene carbonate, and dinitrile compounds.
  • the solvent includes one or more of ether-based solvents, nitrile-based solvents, carbonate-based solvents, and carboxylate-based solvents.
  • the ether solvent includes cyclic ether or chain ether
  • the cyclic ether can be, but not limited to, 1,3-dioxolane (DOL), 1,4-dioxoxane (DX)
  • DOL 1,3-dioxolane
  • DX 1,4-dioxoxane
  • the ether can be specifically, but not limited to, one of dimethoxymethane (DMM), 1,2-dimethoxyethane (DME), diglyme (TEGDME), and ethylene glycol dimethyl ether or more.
  • DDMM dimethoxymethane
  • DME 1,2-dimethoxyethane
  • TEGDME diglyme
  • the nitrile solvent can be specifically, but not limited to, one or more of acetonitrile, glutaronitrile, and malononitrile.
  • Carbonate-based solvents include cyclic carbonates or chain carbonates. Cyclic carbonates can be, but are not limited to, ethylene carbonate (EC), propylene carbonate (PC), ⁇ -butyrolactone (GBL), butylene carbonate One or more of ester (BC) and vinylene carbonate; the chain carbonate can be specifically but 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 carboxylate solvent can be specifically but not limited to methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), butyl propionate, propyl acetate One or more of methyl acetate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, and ethyl trimethyl acetate.
  • MA methyl acetate
  • EA ethyl acetate
  • EP propyl acetate
  • PP propyl propionate
  • PP propyl propionate
  • propyl acetate One or more of methyl acetate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, and ethyl trimethyl acetate.
  • the electrolyte salt is selected from lithium salts.
  • the lithium salt is selected from LiPF 6 , LiPO 2 F 2 , LiBF 4 , LiBOB, LiClO 4 , LiCF 3 SO 3 , LiDFOB, LiN(SO 2 CF 3 ) 2 and LiN(SO 2 ) F) At least one of 2 .
  • the concentration of the electrolyte salt is 0.1 mol/L-8 mol/L.
  • the concentration of the electrolyte salt is 0.5mol/L-4mol/L.
  • the concentration of the electrolyte salt may be 0.5 mol/L, 1 mol/L, 1.5 mol/L, 2 mol/L, 2.5 mol/L, 3 mol/L, 3.5 mol/L or 4 mol/L.
  • Another embodiment of the present invention provides a lithium ion battery, including a positive electrode, a negative electrode, and the above-mentioned non-aqueous electrolyte.
  • the lithium ion battery adopts the above-mentioned non-aqueous electrolyte, a passivation film with excellent performance can be formed on the positive electrode and the negative electrode, thereby effectively improving the cycle performance of the battery.
  • the positive electrode includes a positive electrode active material capable of reversibly intercalating/deintercalating metal lithium ions, preferably, the positive electrode active material is selected from nickel-cobalt-manganese ternary materials, LiFePO 4 , LiCoO 2 , LiMnO 2 , at least one of LiNiMnO 2 , sulfur and composites thereof.
  • the positive electrode material is LiNi x Co y M z L (1-xyz) O 2 , wherein M is selected from Mn or Al, and L is Al, Sr, Mg, Ti, Ca, Zr, Zn, Si, Cu, V or Fe; and 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ x+y+z ⁇ 1.
  • the negative electrode includes a negative electrode active material
  • the negative electrode active material includes one or more of a carbon-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, mesocarbon microspheres, etc.
  • the tin-based negative electrode can include tin, tin carbon, tin oxide, and tin metal compounds
  • the lithium negative electrode can include metal lithium or lithium alloy .
  • the lithium alloy may be at least one of a lithium-silicon alloy, a lithium-sodium alloy, a lithium-potassium alloy, a lithium-aluminum alloy, a lithium-tin alloy, and a lithium-indium alloy.
  • the battery further includes a separator located between the positive electrode and the negative electrode.
  • the diaphragms include ceramic diaphragms, rubberized diaphragms and conventional diaphragms, preferably polyolefins, polyamides, polysulfones, polyphosphazenes, polyethersulfones, polyetheretherketones, polyetheramides and polyethers.
  • polyolefins preferably polyolefins, polyamides, polysulfones, polyphosphazenes, polyethersulfones, polyetheretherketones, polyetheramides and polyethers.
  • One or more of acrylonitrile including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), double-layer PP/PE, double-layer PP/PP and triple-layer PP/PE/PP and other separators.
  • the cathode active material lithium cobalt oxide LiNi 0.5 Co 0.2 Mn 0.3 O 2 , conductive carbon black Super-P and binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 93:4:3, and then dispersed in In N-methyl-2-pyrrolidone (NMP), a positive electrode slurry was obtained.
  • NMP N-methyl-2-pyrrolidone
  • the slurry is evenly coated on both sides of the aluminum foil, dried, calendered and vacuum-dried, and the aluminum lead wires are welded with an ultrasonic welder to obtain a positive plate, the thickness of the plate is 120-150 ⁇ m.
  • a three-layer separator with a thickness of 20 ⁇ m is placed between the positive plate and the negative plate, and then the sandwich structure composed of the positive plate, the negative plate and the separator is wound, and then the rolled body is flattened and placed in an aluminum foil packaging bag. Vacuum bake at 75°C for 48h to obtain the cell to be injected.
  • the electrolyte prepared above was injected into the cells, sealed in vacuum, and left at 45°C for 24 hours.
  • routine formation of the first charging is carried out according to the following steps: 0.05C constant current charging for 180min, 0.1C constant current charging for 180min, 0.2C constant current charging to 3.95V, secondary vacuum sealing, and then further charging with 0.2C current constant current to 4.2V, after 24hrs at room temperature, discharge to 3.0V with a constant current of 0.2C.
  • the formed battery was charged to 4.2V with a constant current of 1C, then charged with a constant voltage until the current dropped to 0.01C, and then discharged to 3.0V with a constant current of 1C. After N cycles of such charge/discharge, the capacity retention rate after the Nth cycle was calculated to evaluate its high temperature cycling performance.
  • Nth cycle capacity retention rate (%) (Nth cycle discharge capacity/first cycle discharge capacity) ⁇ 100%.
  • the formed battery was charged to 4.2V with 1C constant current and constant voltage at room temperature, and the initial discharge capacity and thickness of the battery were measured. Then, after being stored at 60°C for 30 days, the battery was discharged to 3V at 1C, and the retention capacity and recovery of the battery were measured. Capacity and battery thickness after storage. Calculated as follows:
  • Battery capacity retention rate (%) retained capacity / initial capacity ⁇ 100%;
  • Swelling ratio (%) (battery thickness after storage ⁇ initial battery thickness)/initial battery thickness ⁇ 100%.
  • the test results show that the capacity retention rate of its high-temperature cycle is lower than that of Examples 2-6, and the capacity retention rate and capacity recovery rate of high-temperature storage are higher than those of Examples 2-6. 6 is lower by more than 5 percentage points, and the inflation rate is higher than that of Examples 2-6 by more than 5 percentage points.
  • the addition amount of the compound represented by the structural formula 1 of Example 14 is also in the range of 1.0% ⁇ x ⁇ 5.0%
  • the addition amount of the sulfate/sulfonic acid ester compound represented by the structural formula 2 is 1.1%
  • the test results show that the average capacity retention rate of its high-temperature cycle is lower than that of Examples 2-6, while the capacity retention rate and capacity recovery rate of high-temperature storage are both lower than those of Examples 2-6 by more than 3 percentage points, and the inflation rate It is about 5 percentage points higher than that of Examples 2 to 6.
  • the addition amount of the compound represented by the structural formula 1 of Example 16 is also in the range of 0.01% ⁇ x ⁇ 1.0%, the addition amount of the sulfate/sulfonic acid ester compound shown in the structural formula 2 is only 0.9 %, the test results show that the capacity retention rate of its high-temperature cycle and high-temperature storage is about 5 percentage points lower than that of Examples 7-12, and the inflation rate of high-temperature storage is twice as high as that of Examples 7-12 above.
  • Comparative Example 5 when the compound represented by structural formula 1 is not added, the negative electrode SEI is composed of the reduction product of the phosphate compound represented by structural formula 3, and has a large negative electrode impedance. Insufficient protection leads to poor stability of the positive electrode of the battery, and deterioration of high-temperature storage and high-temperature cycle performance.
  • Comparative Example 7 when the content of the compound represented by Structural Formula 1 is greater than 5%, the high temperature performance cannot be significantly improved even if the phosphate compound represented by Structural Formula 3 is added due to the increase of negative electrode film formation resistance.
  • Example 34 the addition amount (x) of the compound represented by the structural formula 1 is in the range of 0.01 to 5%, and the addition amount (z) of the phosphate compound represented by the structural formula 3 It is also in the range of 0.01 to 1.0%, but only Examples 34 to 36 satisfy 0.1% ⁇ x+y ⁇ 2%.
  • Example 37 the content of the compound of structural formula 1 and the phosphoric acid ester shown in structural formula 3 are all too little, The total addition amount of the two is only 0.09%, and the positive and negative protection effects are weak, so the high-temperature storage and high-temperature cycle performance are poor.
  • Example 38 the content of the compound of structural formula 1 and the phosphoric acid ester shown in structural formula 3 was too much, and the total addition amount of the two reached 3.0%, because the electrolyte-electrode interface impedance was too large at this time, resulting in a huge overpotential and The cycle performance is deteriorated, and the high temperature storage performance is also deteriorated due to the oxidative decomposition of the additive itself.
  • the sum of the addition amount of the compound of structural formula 1 and the phosphoric acid ester shown in structural formula 3 needs to meet certain conditions to achieve better comprehensive performance. It can be seen that when 0.1% ⁇ x+y ⁇ 2%, the battery has better performance. comprehensive performance.
  • the addition amount (x) of the compound represented by Structural Formula 1 is in the range of 0.01 to 5%, and the addition amount (z) of the phosphate compound represented by Structural Formula 3-3 is also 0.01 to 5%.
  • the compounds represented by different structural formula 1 were added to the electrolyte, and the high-temperature cycling and high-temperature storage performance of the battery were improved to varying degrees.
  • the compound represented by the structural formula 1 is added to the non-aqueous electrolyte, and the sulfate/sulfonic acid ester compound represented by the structural formula 2 or the phosphoric acid ester compound represented by the structural formula 3 can be used in conjunction with the non-aqueous electrolyte.
  • the inventor found through a large number of experiments that the improvement of the battery performance is related to the ratio and content of the first additive and the second additive.
  • the second additive is a sulfate/sulfonic acid ester compound represented by structural formula 2
  • the mass percentage (x) of the compound represented by structural formula 1 and the sulfuric acid ester/sulfonic acid ester compound represented by structural formula 2 When the mass percentage (y) of the compound satisfies 0.01% ⁇ x ⁇ 1.0%, and 1.0% ⁇ y ⁇ 5.0%, or 1.0% ⁇ x ⁇ 5.0%, and 0.01% ⁇ y ⁇ 1%, the overall performance of the battery is significantly improved .
  • the mass percentage (x) of the compound represented by the structural formula 1 and the mass percentage (z) of the phosphate compound represented by the structural formula 3 satisfy 0.01% ⁇ x ⁇ 5 %, 0.01% ⁇ z ⁇ 1%, and 0.1% ⁇ x+z ⁇ 2%, the overall performance of the battery is significantly improved.

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Abstract

为克服现有电池存在高温存储和高温循环性能不足的问题，本发明提供了一种非水电解液，包括溶剂、电解质盐、第一添加剂和第二添加剂，所述第一添加剂选自如结构式1所示的化合物中的至少一种： A-D-B-E-C 结构式1 其中，A、B、C各自独立地选自含有环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基的基团； D、E各自独立地选自单键、或含有亚烃基、醚键、硫氧双键或碳氧双键的基团；所述第二添加剂选自如结构式2所示的硫酸酯/磺酸酯类化合物和结构式3所示的磷酸酯类化合物中的至少一种，该电解液能够有效提升电池的高温存储和高温循环性能。

Description

一种非水电解液及锂离子电池 技术领域
本发明属于电池材料技术领域，具体涉及一种非水电解液及锂离子电池。
背景技术
锂离子电池因其优良的性能广泛应用于生活生产中，近年来，随着消费类电子产品和新能源汽车的发展，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.提高电池中活性材料的比例等。提升锂离子电池的充电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。
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/电解液界面表现地尤其明显，具体表现为：电池发生产气，内阻快速增长，容量急剧下降。电池产气会导致内压增大，更进一步可能会发展为电池的爆炸、燃烧等危险情况。
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。例如通过在电解液中添加少量的不饱和磷酸酯类或硫酸酯/磺酸酯类添加剂，可在正极表面形成稳定的保护膜，避免电解液与正极材料发生副反应，有效地控制了电池发生产气、内阻快速增长、容量急剧下降的现象。然而，经大量研究发现，不饱和的磷酸酯类或硫酸酯/磺酸酯类添加剂虽然能够控制电池的产气、内阻增长和容量下降等问题，但在高温存储和高温循环性能方面仍不能满足市场需要，还需要进一步改善电池的高温存储和高温循环性能。
发明内容
本发明所解决的技术问题是针对现有含有不饱和的磷酸酯类或硫酸酯/磺酸酯类的锂离子电池高温存储和高温循环性能不能满足市场需要的问题，从而提供一种具有较好的高温循环性能和高温存储性能的非水电解液及锂离子电池。
本发明的目的通过下述技术方案实现：
一方面，本发明提供了一种非水电解液，包括溶剂、电解质盐、第一添加剂和第二添加剂，所述第一添加剂选自如结构式1所示的化合物中的至少一种：
A-D-B-E-C
结构式1
其中，A、B、C各自独立地选自含有环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基的基团；D、E各自独立地选自单键、或含有亚烃基、醚键、硫氧双键或碳氧双键的基团；所述第二添加剂选自如结构式2所示的硫酸酯/磺酸酯类化合物和结构式3所示的磷酸酯类化合物中的至少一种：
Figure PCTCN2022083554-appb-000001
其中，R 14选自氧、含F的C1-C5亚烷基、C1-C5的饱和亚烷基或不饱和亚烃基，R 15选自氢原子、卤素原子或C1-C5的烷基，n选自0～3的整数；
Figure PCTCN2022083554-appb-000002
其中，R 16、R 17、R 18各自独立的选自C1-C5的饱和烃基、不饱和烃基或卤代烃基，且R 16、R 17、R 18中至少有一个为不饱和烃基；以所述非水电解液的总质量为100％计，所述第一添加剂的添加量为0.01～5.0％；所述结构式2所示的硫酸酯/磺酸酯类化合物的添加量为0.01～5.0％；所述结构式3所示的磷酸酯类化合物的添加量为0.01～1.0％。
可选的，A、B、C各自独立地含有的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基和环状酸酐基的数量为1～5，且A、B、C含有的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基和环状酸酐基的总数量小于等于10。
可选的，A、C各自独立地选自结构式4所示的基团：
Figure PCTCN2022083554-appb-000003
其中，n选自0～4的整数，R 1选自氢、卤素、C1～C5的烃基或卤代烃基；R 2、R 3、R 4、R 5、R 6、R 7各自独立地选自C1～C3的亚烃基、C1～C3的烷氧基、氧原子、
Figure PCTCN2022083554-appb-000004
R 2、R 3、R 4中至少一个选自
Figure PCTCN2022083554-appb-000005
且R 2、R 3、R 4中至少一个选自氧原子，R 5、R 6、R 7中至少一个选自
Figure PCTCN2022083554-appb-000006
且R 5、R 6、R 7中至少一个选自氧原子。
可选的，B选自结构式5所示的基团：
Figure PCTCN2022083554-appb-000007
其中，m选自1～4的整数，R 8、R 9、R 10各自独立地选自C1～C3的亚烃基、C1～C3的烷氧基、氧原子、
Figure PCTCN2022083554-appb-000008
R 8、R 9、R 10中至少一个选自
Figure PCTCN2022083554-appb-000009
且R 8、R 9、R 10中至少一个选自氧原子。
可选的，D、E各自独立地选自结构式6所示的基团：
Figure PCTCN2022083554-appb-000010
其中，z选自0～4的整数，R 11和R 13各自独立地选自单键或C1～C5的亚烃基，R 12选自单键、
Figure PCTCN2022083554-appb-000011
Figure PCTCN2022083554-appb-000012
Figure PCTCN2022083554-appb-000013
可选的，D、E各自独立地选自单键或C1～C5的亚烃基，A、B、C各自独立地选自取代或未取代的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基；
优选的，A、B或C经取代时，取代基选自卤素、烃基或卤代烃基，更优选的，A、B或C经取代时，取代基选自卤素、烷基或卤代烷基。
可选的，A与C彼此相同，A与B彼此相同或不同，D与E彼此相同。
可选的，所述结构式2所示的硫酸酯/磺酸酯类化合物选自以下化合物中的至少一种：
Figure PCTCN2022083554-appb-000014
所述结构式3所示的磷酸酯类化合物选自以下化合物中的至少一种：
Figure PCTCN2022083554-appb-000015
可选的，以所述非水电解液的总质量为100％计，所述第一添加剂的添加量记为x，所述结构式2所示的硫酸酯/磺酸酯类化合物的添加量记为y，则这些物质之间满足：
1％＜y≤5％，且0.01％≤x≤1％；或0.01％≤y≤1％，且1％＜x≤5％。
可选的，以所述非水电解液的总质量为100％计，所述第一添加剂的添加量为x，所述结构式3所示的磷酸酯类化合物的添加量为z，则这些物质之间满足：0.1％＜x+z＜2％；
进一步的，优选0.1％＜x＜2％0.01％＜z＜0.5％，且0.1％＜x+z＜2％。
另一方面，本发明还提供了一种锂离子电池，包括正极、负极以及如上所述的非水电解液。
根据本发明提供的非水电解液，在电解液中加入结构式1所示的化合物，同时配合结构式2所示的硫酸酯/磺酸酯类化合物或者结构式3所示的磷酸酯类化合物的使用，在电池化成过程中，发明人推测结构式1添加剂优先于结构式2硫酸酯/磺酸酯类或者结构式3所示的磷酸酯类化合物在负极形成SEI膜，钝化负极表面从而抑制结构式2所示的硫酸酯/磺酸酯或者结构式3所示的磷酸酯在负极的消耗，避免电解液与负极发生副反应，同时使得硫酸酯/磺酸酯或者磷酸酯类化合物更多的在正极表面分解，稳定正极材料结构，抑制高电压下的金属离子溶出，从而达到高温循环和高温存储过程中的性能稳定。
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。
本发明实施例提供了一种非水电解液，包括溶剂、电解质盐、第一添加剂和第二添加剂，所述第一添加剂选自如结构式1所示的化合物中的至少一种：
A-D-B-E-C
结构式1
其中，A、B、C各自独立地选自含有环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基的基团；D、E各自独立地选自单键、或含有亚烃基、醚键、硫氧双键或碳氧双键的基团；所述第二添加剂选自如结构式2所示的硫酸酯/磺酸酯类化合物和结构式3所示的磷酸酯类化合物中的至少一种：
Figure PCTCN2022083554-appb-000016
其中，R 14选自氧、含F的C1-C5亚烷基、C1-C5的饱和亚烷基或不饱和亚烃基，R 15选自氢原子、卤素原子或C1-C5的烷基，n选自0～3的整数；
Figure PCTCN2022083554-appb-000017
其中，R 16、R 17、R 18各自独立的选自C1-C5的饱和烃基、不饱和烃基或卤代烃基，且R 16、R 17、R 18中至少有一个为不饱和烃基；
以所述非水电解液的总质量为100％计，所述第一添加剂的添加量为0.01～5.0％；所述结构式2所示的硫酸酯/磺酸酯类化合物的添加量为0.01～5.0％；
所述结构式3所示的磷酸酯类化合物的添加量为0.01～1.0％。
根据本发明提供的非水电解液，在电解液中加入结构式1所示的化合物，同时配合结构式2所示的硫酸酯/磺酸酯类化合物或者结构式3所示的磷酸酯类化合物的使用，在电池化成过程中，发明人推测结构式1添加剂优先于结构式2所示的硫酸酯/磺酸酯类或者结构式3所示的磷酸酯类化合物在负极形成SEI膜，钝化负极表面从而抑制结构式2所示的硫酸酯/磺酸酯或者结构式3所示的磷酸酯在负极的消耗，避免电解液与负极发生副反应，同时使得结构式2所示的硫酸酯/磺酸酯或者结构式3所示的磷酸酯类化合物更多的在正极表面分解，稳定正极材料结构，抑制高电压下的金属离子溶出，从而达到高温循环和高温存储过程中的性能稳定。
经发明人研究发现，当结构式2所示的硫酸酯/磺酸酯类化合物的添加量为0.01～5.0％时，将0.01～5.0％的结构式1所示第一添加剂加入到非水电解液中，经发明人推测，在电池化成过程中结构式1添加剂优先于结构式2所示的硫酸酯/磺酸酯类化合物还原，在负极表面成膜形成内层SEI，然后结构式2所示的硫酸酯/磺酸酯类化合物再还原形成外层SEI，两者的分解产物包括含硫的有机物与无机物。结构式2所示的硫酸酯/磺酸酯类化合物还原的短链有机产物与内层结构式1的产物在特定物质的催化下会聚合生成长短A-B-A长链型产物，内外层共同组成更加优化的SEI，利于离子传输，避免电解液与负极发生副反应。同时结构式1的化合物明显抑制了结构式2所示的硫酸酯/磺酸酯类化合物的消耗，使得结构式2所示的硫酸酯/磺酸酯类化合物更多的在正极表面分解，稳定正极材料结构，抑制高电压下的金属离子溶出，从而达到高温循环和高温存储过程中的性能稳定。
同理，通过在电解液中添加0.01％～1.0％的结构式3所示的不饱和磷酸酯类化合物可以在正极发生反应形成钝化膜，该钝化膜将电解液与高电压正极界面进行隔绝，从而抑制电解液与正极界面的副反应。但是由于结构式3所示的化合物磷酸酯的LUMO能级较低，容易在负极表面发生成膜反应，显著增大负极阻抗，经发明人研究发现，在此基础上，再加入0.01～5.0％的结构式1所示第一添加剂，推测可以使结构1化合物优先于结构式3所示的磷酸酯类化合物在负极形成SEI，钝化负极表面从而抑制结构式3所示的化合物磷酸酯在负极的消耗，使其更多的在正极发生反应，不仅更好地保护正极，同时还可以改善电池高温存储和高温循环性能。
在一些实施例中，A、B、C各自独立地含有的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状 磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基和环状酸酐基的数量为1～5，且A、B、C的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基和环状酸酐基的总数量小于等于10。
在一些实施例中，A、C各自独立地选自结构式4所示的基团：
Figure PCTCN2022083554-appb-000018
其中，n选自0～4的整数，R 1选自氢、卤素、C1～C5的烃基或卤代烃基；R 2、R 3、R 4、R 5、R 6、R 7各自独立地选自C1～C3的亚烃基、C1～C3的烷氧基、氧原子、
Figure PCTCN2022083554-appb-000019
R 2、R 3、R 4中至少一个选自
Figure PCTCN2022083554-appb-000020
且R 2、R 3、R 4中至少一个选自氧原子，R 5、R 6、R 7中至少一个选自
Figure PCTCN2022083554-appb-000021
且R 5、R 6、R 7中至少一个选自氧原子。
在优选的实施例中，-R 3-R 2-R 4-的组合基团和-R 7-R 5-R 6-的组合基团各自独立地选自
Figure PCTCN2022083554-appb-000022
在一些实施例中，B选自结构式5所示的基团：
Figure PCTCN2022083554-appb-000023
其中，m选自1～4的整数，R 8、R 9、R 10各自独立地选自C1～C3的亚烃基、C1～C3的烷氧基、氧原子、
Figure PCTCN2022083554-appb-000024
R 8、R 9、R 10中至少一个选自
Figure PCTCN2022083554-appb-000025
Figure PCTCN2022083554-appb-000026
且R 8、R 9、R 10中至少一个选自氧原子。
在优选的实施例中，-R 9-R 8-R 10-的组合基团各自独立地选自
Figure PCTCN2022083554-appb-000027
Figure PCTCN2022083554-appb-000028
在一些实施例中，D、E各自独立地选自结构式6所示的基团：
Figure PCTCN2022083554-appb-000029
其中，z选自0～4的整数，R 11和R 13各自独立地选自单键或C1～C5的亚烃基，R 12选自单键、
Figure PCTCN2022083554-appb-000030
Figure PCTCN2022083554-appb-000031
在一些实施例中，A与C彼此相同，A与B彼此相同或不同，D与E彼此相同。
当A与C彼此相同，以及D与E彼此相同时，所述结构式1所示的化合物为对称结构，相比于非对称结构，对称结构的结构式1所示的化合物在合成上更为容易，产品的收率更高，有利于降低生产成本。
在一些实施例中，D、E各自独立地选自单键或C1～C5的亚烃基，A、B、C各自独立地选自取代或未取代的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基。优选的，A、B或C经取代时，取代基选自卤素、烃基或卤代烃基，更优选的，A、B或C经取代时，取代基选自卤素、烷基或卤代烷基。
作为示例，第一添加剂可选自以下化合物中的一种或多种：
Figure PCTCN2022083554-appb-000032
Figure PCTCN2022083554-appb-000033
在一些实施例中，D、E各自独立地选自结构式6所示的基团：
Figure PCTCN2022083554-appb-000034
其中，z选自1～4的整数，R 11和R 13各自独立地选自单键或C1～C5的亚烃基，R 12选自
Figure PCTCN2022083554-appb-000035
Figure PCTCN2022083554-appb-000036
A、B、C各自独立地选自取代或未取代的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基，优选的，A、B或C经取代时，取代基选自卤素、烃基或卤代烃基，更优选的，A、B或C经取代时，取代基选自卤素、烷基或卤代烷基。
作为示例，第一添加剂可选自以下化合物中的一种或多种：
Figure PCTCN2022083554-appb-000037
Figure PCTCN2022083554-appb-000038
在一些实施例中，所述第一添加剂还可选自以下化合物中的一种或多种：
Figure PCTCN2022083554-appb-000039
Figure PCTCN2022083554-appb-000040
需要说明的是，以上是本发明所要求保护的部分化合物，但不限于此，不应理解为对本发明的限制。
本领域技术人员在知晓结构式1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1-1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1-1。
化合物1-2可通过以下方法制成：
将双丙酮-D-甘露醇、碳酸二甲酯、甲醇、碳酸钾和二氧六环等在加热、搅拌下进行反应数小时后，加入一定量的草酸调节溶液pH到中性，过滤、浓缩后获得中间产物3；在中间产物3中加入适量的纯水、碳酸酯、酸等进行水解反应获得中间产物4；然后将中间产物4、二氯亚砜和碳酸酯溶剂在加热的条件下制备得到中间产物5；最后使用高碘酸钠等氧化剂将中间产物5氧化即可得到化合物1-2。
在一些实施例中，以所述非水电解液的总质量为100％计，所述第一添加剂的添加量为0.01～5.0％。具体的，所述添加剂的添加量可以为0.01％、0.02％、0.05％、0.1％、0.5％、1.0％、2.0％、3.0％、4.0％、5.0％。
当所述第一添加剂的添加量过少时，起不到成膜保护作用，对电池性能的改善效果不明显；当所述第一添加剂的添加量过多时，由于在负极界面形成的界面膜过厚，不利于锂离子穿梭，循环性能反而有所劣化，因此，添加适量的结构式1添加剂才能改善电池的循环性能。
在一些实施例中，所述结构式2所示的硫酸酯/磺酸酯类化合物选自以下化合物中的至少一种：
Figure PCTCN2022083554-appb-000041
所述结构式2所示的硫酸酯/磺酸酯类化合物作为成膜添加剂，具有较低的氧化电位，容易在正极材料表面发生氧化反应，参与正极材料表面钝化膜的生成，该钝化膜可以有效抑制电解液溶剂的氧化反应，同时还可以起到正极保护作用，抑制正极材料中过渡金属的溶出。另外，该类化合物中的硅碳键容易断裂而与电解液中微量的HF结合，起到除水除酸的作用，且增加钝化膜中有机成分的含量，增加该钝化膜的韧性。此外，该添加剂中的结构式2所示的硫酸酯/磺酸酯类化合物与结构式1所示第一添加剂协同作用，在负极表面形成致密稳定的SEI膜，有效阻止电解液在负极表面的还原反应与过渡金属的沉积，改善负极与电解液的界面，减缓存储或循环过程中电极界面的副反应，从而改善电池高温存储和高温循环性能。
在一些实施例中，所述结构式3所示的磷酸酯类化合物选自以下化合物中的至少一种：
Figure PCTCN2022083554-appb-000042
所述结构式3所示的磷酸酯类化合物作为正极成膜添加剂，参与正极材料表面钝化膜的生成，该钝化膜隔绝了电解液与正极界面，可以抑制电解液与正极界面的副反应，起到正极保护作用，同时抑制正极材料中过渡金属的溶出，改善电池的阻抗增长与容量损失。此外，该添加剂中的结构式3所示的磷酸酯与结构式1所示第一添加剂协同作用，在负极表面形成致密稳定的SEI膜，有效阻止电解液在负极表面的还原反应与过渡金属的沉积，改善负极与电解液的界面，减缓存储或循环过程中电极界面的副反应，从而改善电池高温存储和高温循环性能。
在一些实施例中，所述第一添加剂的添加量为x，所述结构式2所示的硫酸酯/磺酸酯类化合物的添加量为y，则这些物质之间满足：1％＜y≤5％，且0.01％≤x≤1％；或0.01％≤y≤1％，且1％＜x≤5％。
发明人经研究发现，结构式1所示化合物与结构式2所示的硫酸酯/磺酸酯类化合物配合使用可以改善电池的高温存储和高温循环性能，并且两者之间的比例对电池性能的提升至关重要，两者含量均过低，对电池的性能提升起不到显著作用，两者含量均过高，则会造成产气增大，影响电池的性能。因此，结构式1所示化合物与结构式2所示的硫酸酯/磺酸酯类化合物的总含量必须限定在一定范围内，当1％＜y≤5％，且0.01％≤x≤1％或者0.01％≤y≤1％，且1％＜x≤5％时，电池体系达到高温存储气胀和高温循环性能最佳。
在一些实施例中，所述第一添加剂的添加量为x，所述结构式3所示的磷酸酯类化合物的添加量为z，则这些物质之间满足：0.1％＜x+z＜2％。
结构式1所示化合物与结构式3所示的磷酸酯类化合物配合使用可以改善电池的高低温存储和循环性能，并且两者之间的比例对电池性能的提升至关重要，两者含量均过低，对电池的性能提升起不到显著作用，两者含量均过高，则会造成产气增大，影响电池的性能。发明人经研究发现，当0.1％＜x+z＜2％时，此时负极SEI主要由结构式1的还原产物组成，正极SEI主要由结构式3所示的磷酸酯的氧化产物组成，此时电池具有较低的气胀率以及较好的高温存储、循环性能。
在一些实施例中，所述非水电解液还包括第三添加剂，所述第三添加剂选自氟代碳酸乙烯酯、碳酸亚乙烯酯、二腈化合物中的至少一种。
在一些实施例中，所述溶剂包括醚类溶剂、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，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-CH 3-THF)，2-三氟甲基四氢呋喃(2-CF 3-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(DMM)、1,2-二甲氧基乙烷(DME)、二甘醇二甲醚(TEGDME)、乙二醇二甲醚中的一种或多种。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。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)、碳酸亚乙烯酯中的一种或多种；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。羧酸酯类溶剂具体可以但不限于是乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(EP)、乙酸丁酯、丙酸丙酯(PP)、丙酸丁酯、丙酸甲酯、丙酸乙酯、丁酸甲酯、异丁酸甲酯、三甲基乙酸甲酯、三甲基乙酸乙酯中的一种或多种。
在一些实施例中，所述电解质盐选自锂盐。
在更优选的实施例中，所述锂盐选自LiPF 6、LiPO 2F 2、LiBF 4、LiBOB、LiClO 4、LiCF 3SO 3、LiDFOB、LiN(SO 2CF 3) 2和LiN(SO 2F) 2中的至少一种。
在一些实施例中，所述非水电解液中，所述电解质盐的浓度为0.1mol/L-8mol/L。
在优选的实施例中，所述非水电解液中，所述电解质盐的浓度为0.5mol/L-4mol/L。
具体的，所述电解质盐的浓度可以为0.5mol/L、1mol/L、1.5mol/L、2mol/L、2.5mol/L、3mol/L、3.5mol/L或4mol/L。
本发明的另一实施例提供了一种锂离子电池，包括正极、负极以及如上所述的非水电解液。
所述锂离子电池由于采用了如上所述的非水电解液，能够在正极和负极上形成性能优异的钝化膜，进而有效地提高了电池的循环性能。
在一些实施例中，所述正极包括能够可逆地嵌入/脱嵌金属锂离子的正极活性材料，优选的，所述正极活性材料选自镍钴锰三元材料、LiFePO 4、LiCoO 2、LiMnO 2、LiNiMnO 2、硫及其复合物中的至少一种。
作为进一步优选的，所述正极材料为LiNi xCo yM zL (1-x-y-z)O 2，其中，M选自Mn或Al，L为Al、Sr、Mg、Ti、Ca、Zr、Zn、Si、Cu、V或Fe；且0≤x≤1，0≤y≤1，0≤z≤1，0≤x+y+z≤1。
在一些实施例中，所述负极包括负极活性材料，所述负极活性材料包括碳基负极、锡基负极、锂负极中的一种或多种。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；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。
所述隔膜包括陶瓷隔膜、涂胶隔膜和常规隔膜，优选为聚烯烃类、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。进一步的，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。
以下通过实施例对本发明进行进一步的说明。
实施例1～50和对比例1～8
1)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(LiPF 6)至摩尔浓度为1mol/L，然后按照各表格加入添加剂。添加剂的用量，按照占电解液的总质量的百分比计。
2)正极板的制备
按93:4:3的质量比混合正极活性材料锂钴氧化物LiNi 0.5Co 0.2Mn 0.3O 2，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。
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
在水氧含量分别20ppm、50ppm以下的手套箱中，将上述制备的电解液注入电芯中，经真空封装，45℃搁置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,0.1C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4.2V，常温搁置24hr后，以0.2C的电流恒流放电至3.0V。
性能测试
(1)高温循环性能测试
在45℃条件下，将化成后的电池用1C的电流恒流充电至4.2V，然后恒压充电至电流下降至0.01C，然后以1C的电流恒流放电至3.0V。如此充/放电N次循环后，计算第N次循环后容量的保持率，以评估其高温循环性能。
45℃1C循环N次容量保持率计算公式如下：
第N次循环容量保持率(％)＝(第N次循环放电容量/第一次循环放电容量)×100％。
(2)高温储存性能测试
将化成后的电池在常温下用1C恒流恒压充至4.2V，测量电池初始放电容量及初始电池厚度，然后再60℃储存30天后，以1C放电至3V，测量电池的保持容量和恢复容量及储存后电池厚度。计算公式如下：
电池容量保持率(％)＝保持容量/初始容量×100％；
电池容量恢复率(％)＝恢复容量/初始容量×100％；
气胀率(％)＝(储存后电池厚度-初始电池厚度)/初始电池厚度×100％。
1.1、实施例1～12和对比例1～4得到的测试结果填入表1。
表1
Figure PCTCN2022083554-appb-000043
从表1的测试结果可以看出，当电解液中添加0.01～5％的结构式2所示的硫酸酯/磺酸酯化合物，且 采用结构式1所示的化合物作为添加剂其添加量为0.01～5％时，电池的高温存储性能和高温循环性能比对比例1-4的有大幅度提升。说明在非水电解液中将0.01～5％的结构式2所示的硫酸酯/磺酸酯类化合物与0.01～5％的结构式1所示化合物的配合使用能够在较大范围内对电池的高温存储性能和高温循环性能起到较好的提升作用。由对比例3可以看出，当结构式1所示化合物的质量百分含量大于5％时，即使将两者配合使用，电池的高温存储和高温循环性能也未能显著提升。
1.2、实施例2～6、13、14和对比例1、2得到的测试结果填入表2。
表2
Figure PCTCN2022083554-appb-000044
从表2的测试结果可以看出，实施例2～6中，结构式1所示化合物的添加量(x)均满足1.0％＜x≤5.0％、且结构式2所示的硫酸酯/磺酸酯类化合物的添加量(y)满足0.01％≤y≤1％，而实施例13的结构式2所示的硫酸酯/磺酸酯类化合物的添加量虽然也在0.01％≤y≤1％范围内，但其结构式1的添加量只有0.9％，测试结果显示，其高温循环的容量保持率均比实施例2～6的低，同时高温存储的容量保持率和容量恢复率均比实施例2～6的低5个百分点以上，气胀率比实施例2～6的高5个百分点以上。
同理，实施例14的结构式1所示化合物的添加量虽然也在1.0％＜x≤5.0％范围内，但其结构式2所示的硫酸酯/磺酸酯类化合物的添加量却有1.1％，测试结果显示，其高温循环的容量保持率平均比实施例2～6的低，同时高温存储的容量保持率和容量恢复率均比实施例2～6的低3个百分点以上，气胀率比实施例2～6的高5个百分点左右。
说明在结构式2所示的硫酸酯/磺酸酯类化合物的添加量(y)满足0.01％≤y≤1％，且结构式1所示化合物的添加量(x)满足1.0％＜x≤5.0％时，对电池的高温存储和高温循环性能的提升起到显著作用。
1.3、实施例7～12、15、16和对比例1、2得到的测试结果填入表3。
表3
Figure PCTCN2022083554-appb-000045
Figure PCTCN2022083554-appb-000046
从表3的测试结果可以看出，实施例7～12中，结构式1所示化合物的添加量(x)均满足0.01％≤x≤1.0％、且结构式2所示的硫酸酯/磺酸酯类化合物的添加量均满足1.0％＜y≤5.0％，而实施例15的结构式2所示的硫酸酯/磺酸酯类化合物的添加量虽然也在1.0％＜y≤5.0％范围内，但其结构式1的添加量却有1.1％，测试结果显示，其高温容量保持率平均比实施例7～12的低5个百分点以上。
同理，实施例16的结构式1所示化合物的添加量虽然也在0.01％≤x≤1.0％范围内，但其结构式2所示的硫酸酯/磺酸酯类化合物的添加量却仅有0.9％，测试结果显示，其高温循环和高温存储的容量保持率均比实施例7～12的低5个百分点左右，而高温存储的气胀率均比实施例7～12的高出了一倍以上。
说明结构式2所示的硫酸酯/磺酸酯类化合物的添加量(y)满足1.0％＜y≤5.0％，且结构式1所示化合物的添加量(x)满足0.01％≤x≤1.0％时，对电池的高温存储和高温循环性能的提升起到显著作用。
1.4、实施例17～27和对比例1、2得到的测试结果填入表4。
表4
Figure PCTCN2022083554-appb-000047
从表4的测试结果可以看出，在结构式2所示的硫酸酯/磺酸酯类化合物的添加量(y)满足1.0％＜y≤5.0％，且结构式1所示化合物的添加量(x)满足0.01％≤x≤1.0％时，或者0.01％≤y≤1％，且1.0％＜x≤5.0％时，采用不同结构式1所示的化合物加入到电解液中，电池的高温存储和高温循环性能均有不同程度的提高。
1.5、实施例28～33和对比例5～8得到的测试结果填入表5。
表5
Figure PCTCN2022083554-appb-000048
Figure PCTCN2022083554-appb-000049
从表5的测试结果可以看出，实施例中电解液添加了0.01～1.0％的结构式3所示磷酸酯化合物，且采用结构式1所示的化合物作为第一添加剂其添加量为0.01～5％，电池的高温存储和循环性能均比对比例5～8的大幅提升。
由对比例5可以看出，未添加结构式1所示化合物时，负极SEI由结构式3所示的磷酸酯化合物的还原产物构成，具有较大的负极阻抗，且由于磷酸酯在负极大量消耗，正极保护不足，导致电池正极稳定性不佳，高温存储、高温循环性能劣化。
由对比例6可以看出，未添加结构式3所示的磷酸酯化合物时，高温存储和高温循环性能均不足，这是因为没有磷酸酯钝化正极，造成高温满电态下电解液在正极界面的持续分解。
由对比例7可以看出结构式1所示化合物的含量大于5％时，由于负极成膜阻抗增大，即使添加结构式3所示的磷酸酯化合物，也不能使得高温性能显著提升。
由对比例8可以看出结构式3所示化合物的含量大于1％时，具有较大的负极阻抗，即使添加结构式1所示的化合物，也不能使得高温性能显著提升。
说明在非水电解液中添加结构式3所示的磷酸酯类化合物与0.01～5％的结构式1所示化合物配合使用才能够在较大范围内对电池的高温存储和循环性能均起到较好的提升作用。
1.6、实施例34～38和对比例5～6得到的测试结果填入表6。
表6
Figure PCTCN2022083554-appb-000050
从表6的测试结果可以看出，实施例34～38中，结构式1所示化合物的添加量(x)在0.01～5％范围内，结构式3所示的磷酸酯化合物的添加量(z)也在0.01～1.0％范围内,但是，只有实施例34～36满足0.1％＜x+y＜2％，实施例37中，结构式1化合物与结构式3所示的磷酸酯的含量均过少，两者的总添加量只有0.09％，正负极保护作用均较弱，所以高温存储和高温循环性能较差。实施例38中，结构式1化合物与结构式3所示的磷酸酯的含量均过多，两者的总添加量达到3.0％，由于此时电解液-电极界面阻抗过大，造成巨大的过电势而劣化循环性能，而高温存储性能也由于添加剂本身的氧化分解而劣化。
所以结构式1化合物与结构式3所示的磷酸酯的添加量之和需要满足一定条件才能达到较好的综合性能，可以看到，当0.1％＜x+y＜2％时，电池拥有较好的综合性能。
1.7、实施例39～50和对比例5～6得到的测试结果填入表7。
表7
Figure PCTCN2022083554-appb-000051
从表7的测试结果可以看出，在结构式1所示化合物的添加量(x)在0.01～5％范围内，结构式3-3所示的磷酸酯化合物的添加量(z)也在0.01～1.0％范围内,采用不同结构式1所示的化合物加入到电解液中，电池的高温循环和高温存储性能均有不同程度的提高。
综上所述，本发明通过在非水电解液中加入结构式1所示化合物，同时与结构式2所示的硫酸酯/磺酸酯类化合物或者结构式3所示的磷酸酯类化合物配合使用能够显著改善电池的高温存储和高温循环性能，发明人通过大量的实验发现，电池性能的提升与第一添加剂和第二添加剂的比例以及含量有关。经进一步的研究发现，当第二添加剂为结构式2所示的硫酸酯/磺酸酯类化合物时，结构式1所示化合物的质量百分比(x)以及结构式2所示的硫酸酯/磺酸酯类化合物的质量百分比(y)满足0.01％≤x≤1.0％，且1.0％＜y≤5.0％,或者1.0％＜x≤5.0％，且0.01％≤y≤1％时，电池的综合性能提升显著。当第二添加剂为结构式3所示的磷酸酯类化合物时，结构式1所示化合物的质量百分比(x)以及结构式3所示的磷酸酯类化合物的质量百分比(z)满足0.01％＜x≤5％，0.01％＜z≤1％，且0.1％＜x+z＜2％时，电池的综合性能提升显著。
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 (12)

  1. 一种非水电解液，其特征在于，包括溶剂、电解质盐、第一添加剂和第二添加剂，所述第一添加剂选自如结构式1所示的化合物中的至少一种：
    A-D-B-E-C
    结构式1
    其中，A、B、C各自独立地选自含有环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基的基团；D、E各自独立地选自单键、或含有亚烃基、醚键、硫氧双键或碳氧双键的基团；所述第二添加剂选自如结构式2所示的硫酸酯/磺酸酯类化合物和结构式3所示的磷酸酯类化合物中的至少一种：
    Figure PCTCN2022083554-appb-100001
    其中，R 14选自氧、含F的C1-C5亚烷基、C1-C5的饱和亚烷基或不饱和亚烃基，R 15选自氢原子、卤素原子或C1-C5的烷基，n选自0～3的整数；
    Figure PCTCN2022083554-appb-100002
    其中，R 16、R 17、R 18各自独立的选自C1-C5的饱和烃基、不饱和烃基或卤代烃基，且R 16、R 17、R 18中至少有一个为不饱和烃基；以所述非水电解液的总质量为100％计，所述第一添加剂的添加量为0.01～5.0％；所述结构式2所示的硫酸酯/磺酸酯类化合物的添加量为0.01～5.0％；所述结构式3所示的磷酸酯类化合物的添加量为0.01～1.0％。
  2. 根据权利要求1所述的非水电解液，其特征在于，A、B、C各自独立地含有的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基和环状酸酐基的数量为1～5，且A、B、C含有的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基和环状酸酐基的总数量小于等于10。
  3. 根据权利要求1所述的非水电解液，其特征在于，A、C各自独立地选自结构式4所示的基团：
    Figure PCTCN2022083554-appb-100003
    其中，n选自0～4的整数，R 1选自氢、卤素、C1～C5的烃基或卤代烃基；R 2、R 3、R 4、R 5、R 6、R 7各自独立地选自C1～C3的亚烃基、C1～C3的烷氧基、氧原子、
    Figure PCTCN2022083554-appb-100004
    R 2、R 3、R 4中至少一个选自
    Figure PCTCN2022083554-appb-100005
    且R 2、R 3、R 4中至少一个选自氧原子， R 5、R 6、R 7中至少一个选自
    Figure PCTCN2022083554-appb-100006
    且R 5、R 6、R 7中至少一个选自氧原子。
  4. 根据权利要求1所述的非水电解液，其特征在于，B选自结构式5所示的基团：
    Figure PCTCN2022083554-appb-100007
    其中，m选自1～4的整数，R 8、R 9、R 10各自独立地选自C1～C3的亚烃基、C1～C3的烷氧基、氧原子、
    Figure PCTCN2022083554-appb-100008
    R 8、R 9、R 10中至少一个选自
    Figure PCTCN2022083554-appb-100009
    且R 8、R 9、R 10中至少一个选自氧原子。
  5. 根据权利要求1所述的非水电解液，其特征在于，D、E各自独立地选自结构式6所示的基团：
    Figure PCTCN2022083554-appb-100010
    其中，z选自0～4的整数，R 11和R 13各自独立地选自单键或C1～C5的亚烃基，R 12选自单键、
    Figure PCTCN2022083554-appb-100011
    Figure PCTCN2022083554-appb-100012
  6. 根据权利要求1所述的非水电解液，其特征在于，D、E各自独立地选自单键或C1～C5的亚烃基，A、B、C各自独立地选自取代或未取代的环状碳酸酯基、环状硫酸酯基、环状亚硫酸酯基、环状磺酸酯基、环状砜基、环状亚砜基、环状羧酸酯基或环状酸酐基；
    优选的，A、B或C经取代时，取代基选自卤素、烃基或卤代烃基，更优选的，A、B或C经取代时，取代基选自卤素、烷基或卤代烷基。
  7. 根据权利要求1-6任一项所述的非水电解液，其特征在于，A与C彼此相同，A与B彼此相同或不同，D与E彼此相同。
  8. 根据权利要求1所述的非水电解液，其特征在于，所述第一添加剂选自以下化合物中的一种或多种：
    Figure PCTCN2022083554-appb-100013
    Figure PCTCN2022083554-appb-100014
    Figure PCTCN2022083554-appb-100015
    Figure PCTCN2022083554-appb-100016
    Figure PCTCN2022083554-appb-100017
  9. 根据权利要求1所述的非水电解液，其特征在于，所述结构式2所示的硫酸酯/磺酸酯类化合物选自以下化合物中的至少一种：
    Figure PCTCN2022083554-appb-100018
    所述结构式3所示的磷酸酯类化合物选自以下化合物中的至少一种：
    Figure PCTCN2022083554-appb-100019
  10. 根据权利要求1所述的非水电解液，其特征在于，以所述非水电解液的总质量为100％计，所述第一添加剂的添加量为x，所述硫酸酯/磺酸酯类化合物的添加量为y，则这些物质之间满足：
    1％＜y≤5％，且0.01％≤x≤1％；或0.01％≤y≤1％，且1％＜x≤5％。
  11. 根据权利要求1所述的非水电解液，其特征在于，以所述非水电解液的总质量为100％计，所述第一添加剂的添加量为x，所述磷酸酯类化合物的添加量为z，则这些物质之间满足：0.1％＜x+z＜2％。
  12. 一种锂离子电池，其特征在于，包括正极、负极以及如权利要求1～11任意一项所述的非水电解液。
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