WO2024016897A1 - 一种非水电解液及二次电池 - Google Patents

一种非水电解液及二次电池 Download PDF

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WO2024016897A1
WO2024016897A1 PCT/CN2023/099799 CN2023099799W WO2024016897A1 WO 2024016897 A1 WO2024016897 A1 WO 2024016897A1 CN 2023099799 W CN2023099799 W CN 2023099799W WO 2024016897 A1 WO2024016897 A1 WO 2024016897A1
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aqueous electrolyte
carbonate
lithium
structural formula
compound
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PCT/CN2023/099799
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English (en)
French (fr)
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曹朝伟
周忠仓
陈雪君
王驰
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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
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention belongs to the technical field of energy storage electronic components, and specifically relates to a non-aqueous electrolyte and a secondary battery.
  • power batteries are mainly lithium-ion batteries.
  • Lithium-ion battery cells are mainly composed of positive electrodes, negative electrodes, separators and electrolytes.
  • the lithium ions in the battery's positive electrode material are deintercalated and embedded into the carbon negative electrode through the electrolyte.
  • the electrolyte components will preferentially obtain electrons and react on the surface of the carbon negative electrode to produce compounds such as Li 2 CO 3 , Li 2 O, and LiOH, thus forming a passivation film on the surface of the negative electrode.
  • This passivation film is called the solid electrolyte interface. membrane (SEI).
  • SEI solid electrolyte interface. membrane
  • the SEI film formed during the initial charging process can prevent the electrolyte from further decomposing on the surface of the carbon negative electrode, acting as a lithium ion conductor and allowing only lithium ions to pass through.
  • the electrode may change, causing the SEI film to rupture, which may cause the negative electrode to be exposed to the electrolyte again and continue to react with the electrolyte.
  • gas is produced, causing the internal pressure of the lithium-ion battery to increase and reducing the cycle life of the battery.
  • the electrode volume changes more obviously, and the SEI film is more likely to rupture, resulting in a more obvious decrease in the electrochemical performance of the lithium-ion battery under high temperature conditions. Therefore, the quality of the SEI film seriously affects the high-temperature performance of lithium-ion batteries.
  • the present invention provides a non-aqueous electrolyte and a preparation method thereof.
  • the present invention provides a non-aqueous electrolyte solution, including a non-aqueous organic solvent, an electrolyte salt and an additive.
  • the additive includes a compound represented by Structural Formula 1:
  • Y is selected from O, C1-C5 substituted or unsubstituted alkylene;
  • R 5 is a halogen atom, a C1-C10 substituted or unsubstituted alkoxy group;
  • R 1 , R 2 , R 3 and R 4 are each independently selected from H, halogen atoms Or C1-C5 substituted or unsubstituted hydrocarbon group.
  • Y is selected from O or a C1-C2 substituted or unsubstituted alkylene group;
  • R 5 is one of a halogen atom, a C1-C10 halogenated or non-halogenated alkoxy group;
  • R 4 are each independently selected from H, halogen atom, C1-C5 hydrocarbon group or C1-C5 halogenated hydrocarbon group.
  • X is One of the groups.
  • the compound represented by the structural formula 1 is selected from one or more of the following compounds:
  • the mass percentage of the compound represented by the structural formula 1 is 0.01%-5.0%.
  • the electrolyte salt is selected from lithium salt or sodium salt
  • the lithium salt is selected from LiPF 6 , LiBOB, LiDFOB, LiPO 2 F 2 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiC(SO 2 CF 3 ) 3 , LiN(SO 2 F) 2 , LiClO 4 , LiAlCl 4 , LiCF 3 SO 3 , Li 2 B 10 Cl 10 , LiSO 2 F, LiTOP (lithium trioxalate phosphate), LiDODFP (difluorodioxalate Lithium phosphate), LiOTFP (lithium tetrafluorooxalate phosphate) and at least one of lower aliphatic carboxylic acid lithium salts.
  • LiPF 6 LiBOB, LiDFOB, LiPO 2 F 2 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 )
  • the sodium salt is selected from NaPF 6 , NaClO 4 , NaAsF 6 , NaSbF 6 , NaPOF 4 , NaPO 2 F 2 , NaC 4 BO 8 , NaC 2 BF 2 O 4 , NaODFB, NaN(SO 2 C 2 F 5 ) 2 , NaN(SO 2 CF 3 )(SO 2 C 4 F 9 ) 2 , at least one of NaC(SO 2 CF 3 ) and Na(C 2 F 5 )PF 3 .
  • the non-aqueous organic solvent includes one or more of ether solvents, nitrile solvents, carbonate solvents and carboxylate solvents.
  • the additive also includes at least one of cyclic sulfate ester compounds, sultone compounds, cyclic carbonate compounds, phosphate ester compounds, borate ester compounds and nitrile compounds;
  • the additive amount is 0.01% to 30%.
  • the cyclic sulfate compound is selected from vinyl sulfate, propylene sulfate, vinyl methyl sulfate, at least one of;
  • the sultone compound is selected from 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, at least one of;
  • the cyclic carbonate compound is selected from vinylene carbonate, ethylene ethylene carbonate, methylene vinyl carbonate, fluoroethylene carbonate, trifluoromethylethylene carbonate, bisfluoroethylene carbonate or structural formula At least one of the compounds shown in 2,
  • R 21 , R 22 , R 23 , R 24 , R 25 , and R 26 are each independently selected from one of hydrogen atoms, halogen atoms, and C1-C5 groups;
  • the phosphate compound is selected from at least one of tris(trimethylsilane)phosphate, tris(trimethylsilane)phosphite or the compound represented by structural formula 3:
  • R 31 , R 32 , and R 33 are each independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, -Si(C m H 2m+1 ) 3 , and m is 1 to is a natural number of 3, and at least one of R 31 , R 32 , and R 33 is an unsaturated hydrocarbon group;
  • the borate compound is selected from at least one of tris(trimethylsilane)borate and tris(triethylsilane)borate;
  • the nitrile compound is selected from succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelonitrile, and sebaconitrile. of one or more.
  • the present invention provides a secondary battery including a positive electrode, a negative electrode and the non-aqueous electrolyte as described above.
  • the inventor found that adding the compound represented by Structural Formula 1 as an additive can play a greater role in the film formation of the non-aqueous electrolyte on the positive and negative electrodes at a smaller amount.
  • the improvement effect is that the formed passivation film has greater flexibility, high stability, and relatively slow impedance growth, which improves the performance stability of the positive and negative electrode materials in long-term cycles and extends the cycle life of the battery.
  • the compound shown in structural formula 1 has an asymmetric bicyclic structure, with a seven-membered ring cyclic sulfate ester structure on one side and a five-membered or six-membered ring structure on the other side.
  • the structural formula The compound shown in 1 forms structures with different chain lengths after ring opening on both sides, which has a larger space for movement and is more conducive to Form a passivation film with better toughness.
  • the stability of the passivation film at high temperatures is particularly excellent. Therefore, batteries prepared using the non-aqueous electrolyte provided by this application are particularly suitable for high temperature conditions. The following work improves the environmental adaptability of the battery.
  • One embodiment of the present invention provides a non-aqueous electrolyte solution, including a non-aqueous organic solvent, an electrolyte salt and additives.
  • the additives include the compound represented by Structural Formula 1:
  • Y is selected from O, C1-C5 substituted or unsubstituted alkylene;
  • R 5 is a halogen atom, a C1-C10 substituted or unsubstituted alkoxy group;
  • R 1 , R 2 , R 3 and R 4 are each independently selected from H, halogen atoms Or C1-C5 substituted or unsubstituted hydrocarbon group.
  • the compound represented by Structural Formula 1 can greatly improve the film formation of non-aqueous electrolyte on the positive and negative electrodes at a smaller amount, and the formed passivation film has greater flexibility. properties, high stability, and relatively slow impedance growth, which improves the performance stability of positive and negative electrode materials in long-term cycles and extends the cycle life of the battery. It is speculated that the compound shown in Structural Formula 1 has an asymmetric bicyclic structure. One side of the compound has a seven-membered ring cyclic sulfate structure, and the other side has a five-membered or six-membered ring structure.
  • the compound shown in Structural Formula 1 forms different chain lengths after ring opening on both sides.
  • the structure has a larger space for movement and is more conducive to forming a passivation film with better toughness.
  • the stability of the passivation film at high temperatures is particularly excellent. Therefore, batteries prepared using the non-aqueous electrolyte provided by this application are particularly suitable for high temperature conditions. The following work improves the environmental adaptability of the battery.
  • Y is selected from O or methylene;
  • R 5 is a halogen atom, a C1-C10 halogenated or non-halogenated alkoxy group;
  • R 1 , R 2 , R 3 , and R 4 are each independent is selected from H, halogen atoms, C1-C5 hydrocarbon groups or C1-C5 halogenated hydrocarbon groups.
  • X is One of the groups.
  • the compound represented by the structural formula 1 is a combined bicyclic structure of one of cyclic sulfate ester and cyclic carboxylic acid ester, cyclic carbonate ester, and cyclic phosphate ester, which can further improve the high-temperature stability of the passivation film.
  • the compound shown in Structural Formula 1 can form an inorganic component containing lithium sulfate, and at the same time can polymerize to form an organic component containing heteroatoms, which can reduce the amount of gas generation and is conducive to the synthesis of different film-forming elements for the passivation film. The effect of this is to obtain a passivation film with excellent high temperature stability.
  • the passivation film containing inorganic components and organic components is more uniform on the atomic scale. It can not only increase the lithium ion conduction rate, but also protect the positive and negative electrode structures, improve the stability of battery materials, and better isolate the positive and negative electrodes.
  • the contact between the material and the electrolyte reduces battery polarization, inhibits impedance growth, improves the high-temperature performance of the battery, and extends the cycle life of the battery.
  • the compound represented by Structural Formula 1 is selected from one or more of the following compounds:
  • the compound represented by the structural formula 1 can be prepared by the following method:
  • the compound shown in Structural Formula 1 as an example selected from bicyclic sulfate carbonate, it can be prepared by the following method: using a transesterification reaction between tetrahydric alcohol and dimethyl carbonate to obtain a carbonic acid polyol ester, and then halogenating the carbonic acid polyol ester with The thionyl reaction obtains bicyclic sulfite carbonate, and then the bicyclic sulfite carbonate is reacted with an oxidizing agent to obtain bicyclic sulfite carbonate.
  • the specific reaction formula is as follows:
  • the compound shown in Structural Formula 1 as an example selected from bicyclic sulfate, it can be prepared by the following method: reacting tetrahydric alcohol with thionyl halide to obtain bicyclic sulfite, and then reacting bicyclic sulfite with an oxidizing agent to obtain bicyclic sulfite.
  • Sulfate ester the specific reaction formula is as follows:
  • the compound shown in Structural Formula 1 selected from bicyclic sulfate carboxylic acid ester can be prepared by the following method: using 4,5-dihydroxy-3-hydroxymethyl-valeric acid catalytic dehydration to prepare dihydroxylactone, and then It reacts with thionyl chloride to form bicyclic sulfite carboxylate, and then reacts with an oxidizing agent to obtain bicyclic sulfite carboxylate.
  • the specific reaction formula is as follows:
  • the compound shown in Structural Formula 1 as an example selected from bicyclic sulfite phosphate, it can be prepared by the following method: reacting tetrahydric alcohol carbonate monoester with thionyl halide to obtain bicyclic sulfite carbonate, and then hydrolyzing it to obtain dihydroxy. Sulfite further reacts with methylphosphoryl chloride to obtain bicyclic sulfite phosphate, and then reacts with an oxidizing agent to obtain bicyclic sulfite phosphate.
  • the specific reaction formula is as follows:
  • the mass percentage of the compound represented by Structural Formula 1 is 0.01%-5.0%.
  • the mass percentage of the compound represented by the structural formula 1 can be 0.01%, 0.02%, 0.05%, 0.08%, 1.0%, 1.1%. ,1.3%,1.5%,1.8%,2.0%,2.3%, 2.7%, 3.0%, 3.4%, 3.7%, 3.9%, 4.1%, 4.4%, 4.7% or 5.0%.
  • the mass percentage of the compound represented by the structural formula 1 is 0.1%-3.0%.
  • the mass percentage of the compound represented by the structural formula 1 is 0.5%-3.0%.
  • the added amount of the compound represented by the structural formula 1 affects the quality of the passivation film on the surface of the positive and negative electrodes.
  • the content of the compound represented by the structural formula 1 is too low, it is difficult to form a complete passivation film on the surface of the positive and negative electrodes.
  • the passivation film does not significantly improve the performance of the secondary battery; when the content of the compound shown in Structural Formula 1 is too high, it is easy to cause the film thickness on the surface of the positive and negative electrodes to be too large, increasing the cross-sectional impedance of the positive and negative electrodes, and Deteriorating the high-temperature performance of the battery.
  • the non-aqueous electrolyte solution can be applied to different types of secondary batteries.
  • the electrolyte salt includes one or more of lithium salt or sodium salt.
  • the electrolyte salt is selected from lithium salts; when the non-aqueous electrolyte is used in sodium ion batteries, the electrolyte salt is selected from sodium salts.
  • the electrolyte salt is selected from lithium salts or sodium salts.
  • the lithium salt is selected from LiPF 6 , LiBOB, LiDFOB, LiPO 2 F 2 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiC(SO 2 CF 3 ) 3 , LiN(SO 2 F) 2 , LiClO 4 , LiAlCl 4 , LiCF 3 SO 3 , Li 2 B 10 Cl 10 , LiSO 2 F, LiTOP (lithium trioxalate phosphate), At least one of LiDODFP (lithium difluorodioxalate phosphate), LiOTFP (lithium tetrafluorooxalate phosphate) and lower aliphatic carboxylic acid lithium salt.
  • LiPF 6 LiBOB, LiDFOB, LiPO 2 F 2 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 ,
  • the sodium salt is selected from the group consisting of NaPF 6 , NaClO 4 , NaAsF 6 , NaSbF 6 , NaPOF 4 , NaPO 2 F 2 , NaC 4 BO 8 , NaC 2 BF 2 O 4 , NaODFB, NaN(SO 2 At least one of C 2 F 5 ) 2 , NaN(SO 2 CF 3 )(SO 2 C 4 F 9 ) 2 , NaC (SO 2 CF 3 ) and Na(C 2 F 5 )PF 3 .
  • the concentration of the lithium salt in the non-aqueous electrolyte is 0.1 mol/L to 8 mol/L. In a preferred embodiment, the concentration of the lithium salt in the non-aqueous electrolyte is 0.5 mol/L to 2.5 mol/L. Specifically, in the non-aqueous electrolyte solution, the concentration of the lithium salt can be 0.5 mol/L, 1 mol/L, 1.5 mol/L, 2 mol/L, or 2.5 mol/L.
  • the concentration of the sodium salt in the non-aqueous electrolyte is 0.1 mol/L to 2 mol/L. In a preferred embodiment, the concentration of the sodium salt in the non-aqueous electrolyte is 0.4 mol/L to 1.5 mol/L. Specifically, in the non-aqueous electrolyte, the concentration of the sodium salt can be 0.1 mol/L, 0.4 mol/L, 0.5 mol/L, 0.7 mol/L, 0.8 mol/L, 0.9 mol/L, 1 mol /L, 1.2mol/L, 1.5mol/L, 2mol/L.
  • the non-aqueous organic solvent includes one or more of ether solvents, nitrile solvents, carbonate solvents and carboxylate solvents.
  • ether solvents include cyclic ethers or chain ethers, preferably chain ethers with 3 to 10 carbon atoms and cyclic ethers with 3 to 6 carbon atoms.
  • Cyclic ethers can be, but are not limited to, It is 1,3-dioxopentane (DOL), 1,4-dioxane (DX), crown ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH 3 -THF), 2-trihydrofuran One or more of fluoromethyltetrahydrofuran (2-CF 3 -THF); the chain ether can be, but is not limited to, dimethoxymethane, diethoxymethane, ethoxymethoxymethane , Ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether.
  • chain ether and lithium ion Dimethoxymethane, diethoxymethane, and ethoxymethoxymethane which have low viscosity and can impart high ionic conductivity, are particularly preferred because they have high solvating ability and can improve ion dissociation properties.
  • One type of ether compound may be used alone, or two or more types may be used in any combination and ratio.
  • the amount of the ether compound added is not particularly limited and is arbitrary within the range that does not significantly destroy the effect of the high-pressure lithium ion battery of the present invention. When the non-aqueous solvent volume ratio is 100%, the volume ratio is usually 1% or more, and the preferred volume is 100%.
  • the volume ratio is 2% or more, and more preferably, the volume ratio is 3% or more.
  • the volume ratio is usually 30% or less, preferably 25% or less, and more preferably 20% or less.
  • the total amount of the ether compounds may satisfy the above range.
  • the amount of the ether compound added is within the above-mentioned preferred range, it is easy to ensure the improvement effect of the ion conductivity by increasing the degree of lithium ion dissociation and reducing the viscosity of the chain ether.
  • the negative electrode active material is a carbon-based material, the phenomenon of co-intercalation of chain ether and lithium ions can be suppressed, so the input-output characteristics and charge-discharge rate characteristics can be achieved within an appropriate range.
  • the nitrile solvent may be, but is not limited to, one or more of acetonitrile, glutaronitrile, and malononitrile.
  • the carbonate solvent includes cyclic carbonate or chain carbonate.
  • the cyclic carbonate can be, but is not limited to, ethylene carbonate (EC), propylene carbonate (PC), and ⁇ -butyrolactone.
  • EC ethylene carbonate
  • PC propylene carbonate
  • ⁇ -butyrolactone One or more of (GBL), butylene carbonate (BC);
  • the chain carbonate can be, but is not limited to, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) ), one or more of dipropyl carbonate (DPC).
  • DMC dimethyl carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • DPC dipropyl carbonate
  • the content of the cyclic carbonate is not particularly limited and is arbitrary within the range that does not significantly damage the effect of the lithium ion battery of the present invention.
  • the lower limit of the content is relative to the total amount of solvent in the non-aqueous electrolyte.
  • the volume ratio is usually 3% or more, and preferably the volume ratio is 5% or more.
  • the upper limit of the volume ratio is usually 90% or less, preferably 85% or less, and more preferably 80% or less.
  • the content of the chain carbonate is not particularly limited, but is usually 15% or more by volume, preferably 20% or more by volume, and more preferably 25% or more by volume relative to the total amount of solvent in the non-aqueous electrolyte solution.
  • the volume ratio is usually 90% or less, preferably 85% or less, and more preferably 80% or less.
  • the viscosity of the non-aqueous electrolyte solution can be easily brought into an appropriate range, thereby suppressing a decrease in ion conductivity, thereby contributing to bringing the output characteristics of the non-aqueous electrolyte battery into a favorable range.
  • the total amount of the linear carbonates may satisfy the above range.
  • chain carbonates having fluorine atoms may also be preferably used.
  • the number of fluorine atoms contained in the fluorinated linear carbonate is not particularly limited as long as it is 1 or more, but it is usually 6 or less, preferably 4 or less.
  • these fluorine atoms may be bonded to the same carbon or to different carbons.
  • the fluorinated chain carbonate include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, and fluorinated diethyl carbonate derivatives.
  • Carboxylic acid ester solvents include cyclic carboxylic acid esters and/or chain carbonic acid esters.
  • cyclic carboxylic acid esters include one or more of ⁇ -butyrolactone, ⁇ -valerolactone, and ⁇ -valerolactone.
  • chain carbonates include methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate. of one or more.
  • the sulfone solvent includes cyclic sulfone and chain sulfone.
  • cyclic sulfone it usually has 3 to 6 carbon atoms, preferably 3 to 5 carbon atoms.
  • chain sulfone In the case of sulfone, it is usually a compound having 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms.
  • sulfone solvent There is no special limit to the amount of sulfone solvent added, as long as it does not significantly damage the effect of the lithium-ion battery of the present invention. The range is arbitrary.
  • the volume ratio is usually 0.3% or more, preferably 0.5% or more, and more preferably 1% or more relative to the total amount of solvent in the non-aqueous electrolyte solution.
  • the volume ratio is usually 40 % or less, preferably the volume ratio is 35% or less, and more preferably the volume ratio is 30% or less.
  • the total amount of the sulfone solvents may satisfy the above range.
  • the added amount of the sulfone solvent is within the above range, an electrolyte solution excellent in high-temperature storage stability tends to be obtained.
  • the solvent is a mixture of cyclic carbonate and chain carbonate.
  • the additive further includes at least one of cyclic sulfate ester compounds, sultone compounds, cyclic carbonate compounds, phosphate ester compounds, borate ester compounds and nitrile compounds. ;
  • the additive amount is 0.01% to 30%.
  • the cyclic sulfate compound is selected from vinyl sulfate, propylene sulfate, vinyl methyl sulfate, at least one of them.
  • the sultone compound is selected from 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, at least one of;
  • the cyclic carbonate compound is selected from vinylene carbonate, ethylene carbonate, methylene vinyl carbonate, fluoroethylene carbonate, trifluoromethylethylene carbonate, bisfluoroethylene carbonate or structural formula At least one of the compounds shown in 2,
  • R 21 , R 22 , R 23 , R 24 , R 25 , and R 26 are each independently selected from hydrogen atoms, halogen atoms, and C1-C5 groups. Specifically, the compound represented by the structural formula 2 includes at least one of them.
  • the phosphate compound is selected from at least one of tris(trimethylsilane)phosphate, tris(trimethylsilane)phosphite or the compound represented by structural formula 3:
  • R 31 , R 32 , and R 33 are each independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, -Si(C m H 2m+1 ) 3 , and m is 1 to is a natural number of 3, and at least one of R 31 , R 32 , and R 33 is an unsaturated hydrocarbon group;
  • the phosphate ester compound may be tripropargyl phosphate, dipropargyl methyl phosphate, dipropargyl ethyl phosphate, dipropargyl propyl phosphate, or diacetylene phosphate.
  • the borate compound is selected from at least one of tris(trimethylsilane)borate and tris(triethylsilane)borate;
  • the nitrile compound is selected from succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelonitrile, and sebaconitrile. of one or more.
  • the additives may also include other additives that can improve battery performance: for example, additives that improve battery safety performance, specifically flame retardant additives such as fluorinated phosphates, cyclophosphazene, or tert-amylbenzene. , tert-butylbenzene and other anti-overcharge additives.
  • the amount of any optional substance in the additives added to the non-aqueous electrolyte is less than 10%, preferably, the amount added is 0.1-5%, more preferably , the addition amount is 0.1% to 2%.
  • the amount of any optional substance in the additives can be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2% , 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8%, 8.5 %, 9%, 9.5%, 10%.
  • the added amount of the fluorinated ethylene carbonate is 0.05% to 30% based on the total mass of the non-aqueous electrolyte being 100%.
  • Another embodiment of the present invention provides a secondary battery including a positive electrode, a negative electrode and the non-aqueous electrolyte as described above.
  • the positive electrode includes a positive electrode material layer and a positive electrode current collector, and the positive electrode material layer is formed on the surface of the positive electrode current collector.
  • the positive electrode current collector is selected from metal materials that can conduct electrons.
  • the positive electrode current collector includes one or more of Al, Ni, tin, copper, and stainless steel.
  • the positive electrode current collector is selected from aluminum foil.
  • the positive electrode material layer includes a positive electrode active material, a positive electrode binder and a positive electrode conductive agent.
  • the positive electrode binder includes polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, tetrafluoroethylene- Copolymer of perfluoroalkyl vinyl ether, copolymer of ethylene-tetrafluoroethylene, copolymer of vinylidene fluoride-tetrafluoroethylene, copolymer of vinylidene fluoride-trifluoroethylene, copolymer of vinylidene fluoride-trichloroethylene Copolymers, vinylidene fluoride-fluorovinyl copolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers, thermoplastic polyimides, polyethylene and poly
  • the positive conductive agent includes one or more of conductive carbon black, conductive carbon balls, conductive graphite, conductive carbon fiber, carbon nanotubes, graphene or reduced graphene oxide.
  • the cathode includes a cathode material layer containing a cathode active material.
  • the type of the cathode active material is not particularly limited and can be selected according to actual needs, as long as it can reversibly intercalate/deintercalate metal ions (lithium ions or sodium ions) cathode active material or conversion cathode material.
  • the battery is a lithium ion battery
  • its positive active material can be selected from LiFe 1-x' M' x' PO 4 , LiMn 2-y' M y' O 4 and LiN x Co y Mn z
  • M 1-xyz O 2 wherein M' is selected from one of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti
  • M is selected from one or more kinds of Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, and 0 ⁇ x' ⁇ 1,0 ⁇ y' ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x ⁇ 1, 0 ⁇ z ⁇ 1, x+y+z ⁇ 1
  • the positive active material can also be selected from sulfide and selenide , one or more of the halides.
  • the positive active material can be selected from LiCoO 2 , LiFePO 4 , LiFe 0.8 Mn 0.2 PO 4 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 One or more of O 2 , LiNi 0.5 Co 0.2 Mn 0.2 Al 0.1 O 2 , LiMn 2 O 4 , LiNi 0.5 Co 0.2 Al 0.3 O 2 .
  • the battery is a sodium ion battery
  • its positive active material can be selected from over-plated metal oxides, over-plated metal sulfides, phosphorus-based materials, phosphate materials, sulfate materials, titanate materials, One or more Prussian blue materials.
  • the chemical formula of the over-plated metal oxide and the over-plated metal sulfide is M1 x N y , and M1 can be selected from one or more of Fe, Co, Ni, Cu, Mn, Sn, Mo, Sb, and V.
  • the chemical formula of the phosphate is Na 3 (MO 1-x PO 4 ) 2 F 1+2x , 0 ⁇ x ⁇ 1, M is selected from Al, At least one of V, Ge, Fe and Ga, more preferably, the phosphate is Na 3 (VPO 4 ) 2 F 3 or Na 3 (VOPO 4 ) 2 F; and/or the phosphate is The chemical formula is Na 2 MPO 4 F, and M is selected from at least one of Fe and Mn.
  • the phosphate is Na 2 FePO 4 F or Na 2 MnPO 4 F;
  • the chemical formula of the sulfate is Na 2 M(SO 4 ) 2 ⁇ 2H 2 O
  • M can be selected from at least one of Cr, Fe, Co, Ni, Cu, Mn, Sn, Mo, Sb, and V;
  • the titanate material can be selected from Na 2 Ti 3 O 7 , Na 2 Ti 6 O 13 , At least one of Na 4 Ti 5 O 12 , Li 4 Ti 5 O 12 , and NaTi 2 (PO 4 ) 3 ;
  • the molecular formula of the Prussian blue material is Na x M[M'(CN) 6 ] y ⁇ zH 2 O, where M is a transition metal, M′ is a transition metal, 0 ⁇ x ⁇ 2, 0.8 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 20, more preferably, the Prussian blue material is Na x Mn[ Fe(CN) 6 ] y ⁇ nH 2 O (0 ⁇ x ⁇ 2, 0 ⁇
  • the negative electrode includes a negative electrode material layer including a negative electrode active material.
  • the secondary battery when the secondary battery is a lithium-ion battery, its negative active material includes at least one of a carbon-based negative electrode, a silicon-based negative electrode, a tin-based negative electrode, and a lithium negative electrode.
  • the carbon-based negative electrode can include graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, etc.
  • the silicon-based negative electrode can include silicon materials, silicon oxides, silicon-carbon composite materials, silicon alloy materials, etc.
  • the tin-based negative electrode can It can include tin, tin carbon, tin oxide, and tin metal compounds
  • the lithium negative electrode can include metallic lithium or lithium alloy.
  • the lithium alloy may specifically be at least one of lithium silicon alloy, lithium sodium alloy, lithium potassium alloy, lithium aluminum alloy, lithium tin alloy and lithium indium alloy.
  • the secondary battery when the secondary battery is a sodium-ion battery, its negative active material includes metallic sodium, graphite, soft carbon, hard carbon, carbon fiber, mesophase carbon microspheres, silicon-based materials, tin-based materials, At least one of lithium titanate or other metals that can form alloy materials with sodium.
  • the alloy material can also be selected from at least one of Si, Ge, Sn, Pb, Sb and C.
  • the graphite can be selected from at least one of artificial graphite, natural graphite and modified graphite.
  • the silicon-based material can be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, and silicon alloys; the tin-based material can be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. A sort of.
  • the negative electrode material layer further includes a negative electrode binder and a negative electrode conductive agent, and the negative electrode active material, the negative electrode binder and the negative electrode conductive agent are blended to obtain the negative electrode material layer.
  • the selectable ranges of the negative electrode binder and the negative electrode conductive agent are the same as those of the positive electrode binder and the positive electrode conductive agent respectively, and will not be described again here.
  • the negative electrode further includes a negative electrode current collector, and the negative electrode material layer is formed on the surface of the negative electrode current collector.
  • the negative electrode current collector is selected from metal materials that can conduct electrons.
  • the negative electrode current collector includes one or more of Al, Ni, tin, copper, and stainless steel.
  • the negative electrode current collector is selected from copper foil.
  • the lithium ion battery further includes a separator, and the separator is located between the positive electrode sheet and the negative electrode sheet.
  • the separator can be an existing conventional separator, and can be a polymer separator, non-woven fabric, etc., including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), double-layer PP/PE, double-layer PP /PP and three-layer PP/PE/PP and other separators.
  • This embodiment takes the preparation of lithium-ion batteries as an example to illustrate the present invention, including the following steps:
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • LiPF 6 lithium hexafluorophosphate
  • the cathode active material lithium nickel cobalt manganese oxide LiNi 0.5 Co 0.2 Mn 0.3 O 2 , conductive carbon black Super-P and binder polyvinylidene fluoride (PVDF) in a mass ratio of 93:4:3, and then combine them Dispersed in N-methyl-2-pyrrolidone (NMP) to obtain positive electrode slurry.
  • NMP N-methyl-2-pyrrolidone
  • the slurry is evenly coated on both sides of the aluminum foil, dried, rolled and vacuum dried, and the aluminum lead wire is welded with an ultrasonic welder to obtain a positive plate.
  • the thickness of the plate is between 120-150 ⁇ m.
  • a negative electrode slurry is obtained.
  • the slurry is coated on both sides of the copper foil, dried, rolled and vacuum dried, and a nickel lead wire is welded with an ultrasonic welder to obtain a negative plate.
  • the thickness of the plate is between 120-150 ⁇ m.
  • the electrolyte prepared above was injected into the battery core, sealed in a vacuum, and left to rest for 24 hours.
  • Examples 2 to 16 are used to illustrate the lithium-ion battery and its preparation method disclosed in the present invention, including most of the operating steps in Example 1, and the differences are:
  • Comparative Examples 1 to 6 are used to comparatively illustrate the lithium-ion battery and its preparation method disclosed in the present invention, including most of the operating steps in Example 1, and the differences are:
  • Battery capacity retention rate (%) last discharge capacity/first discharge capacity ⁇ 100%.
  • Example 4 and Comparative Examples 2 to 6 that compared with conventional film-forming additives and their combinations, such as carbon Vinylene sulfate (VC), vinyl sulfate (DTD), fluoroethylene carbonate (FEC) and 1,3 propane sultone (PS) are used as additives, using the compound represented by the structural formula 1 provided by this application, It can more significantly improve the storage performance and cycle performance of lithium-ion batteries at high temperatures and reduce the battery expansion rate, indicating that compared with conventional film-forming additives, the passivation film formed by the compound shown in Structural Formula 1 has better high-temperature stability .
  • conventional film-forming additives and their combinations such as carbon Vinylene sulfate (VC), vinyl sulfate (DTD), fluoroethylene carbonate (FEC) and 1,3 propane sultone (PS) are used as additives, using the compound represented by the structural formula 1 provided by this application, It can more significantly improve the storage performance and cycle performance of lithium-ion batteries at high temperatures and reduce the battery
  • This embodiment takes the preparation of a sodium-ion battery as an example to illustrate the present invention, which includes the following steps:
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • the negative active material spherical hard carbon, conductive carbon black Super-P, binder styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) at a mass ratio of 97:1:1:1, and then disperse them in In deionized water, the negative electrode slurry was obtained.
  • the slurry is coated on both sides of the aluminum foil, dried, rolled and vacuum dried, and aluminum or nickel lead wires are welded with an ultrasonic welder to obtain a negative electrode sheet with a thickness between 80-300 ⁇ m.
  • Examples 18 to 33 are used to illustrate the sodium ion battery and its preparation method disclosed in the present invention, including most of the operating steps in Example 1, and the differences are:
  • Comparative Examples 7 to 10 are used to comparatively illustrate the sodium ion battery and its preparation method disclosed in the present invention, including most of the operating steps in Example 1, and the differences are:
  • the sodium-ion battery prepared above was subjected to the following performance tests:
  • the formed sodium-ion battery was left to stand at 45°C for 2 hours, charged at a constant current of 0.5C to 4.0V, then charged at a constant voltage to a current of 0.03C, and then discharged at a constant current of 1C to 1.5V for 200 cycles. week.
  • Battery capacity retention rate (%) capacity D2/initial capacity D1 ⁇ 100%.
  • the formed sodium ion battery is charged at room temperature with a constant current of 0.5C to 4.0V, then charged with a constant voltage until the current drops to 0.03C, and then discharged with a constant current of 1C to 1.5V, and the initial discharge capacity of the battery is measured.
  • D1 Initial battery volume V1 and initial impedance F1. Then charge to full power and store in 60°C environment for 30 days. Discharge to 3V at 1C. Measure the battery’s retention capacity D2, recovery capacity D3, impedance F2 after storage and the battery after storage. Volume V2.
  • the compound represented by Structural Formula 1 plays a similar role in lithium-ion batteries.
  • the compound represented by Structural Formula 1 is added to the non-aqueous electrolyte of a sodium-ion battery. , can also play a role in improving the high-temperature cycle capacity retention rate, high-temperature storage capacity retention rate, capacity recovery rate and volume expansion rate of sodium-ion batteries, indicating that the compound represented by structural formula 1 is decomposed on the surface of the positive and negative electrodes.
  • the chemical film has high high-temperature stability, improves the performance stability of positive and negative electrode materials in long-term cycles, and improves the cycle performance and storage performance of sodium-ion batteries at high temperatures.
  • Example 20 and Comparative Examples 8-10 that compared with conventional film-forming additives and their combinations, such as vinylene carbonate (VC), vinyl sulfate (DTD) and fluoroethylene carbonate ( FEC), using the compound represented by Structural Formula 1 provided by this application as an additive can more significantly improve the storage performance and cycle performance of sodium-ion batteries at high temperatures, and reduce the battery expansion rate, indicating that compared with conventional film-forming additives,
  • the passivation film formed by the compound represented by Structural Formula 1 has better high-temperature stability.

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Abstract

一种非水电解液、包括非水电解液的二次电池。非水电解液包括非水有机溶剂、电解质盐和添加剂，所述添加剂包括结构式1所示的化合物，其中，Y选自O、C1-C5的取代或未取代的亚烃基；X为AA，BB，CC基团中的一种，R 5为卤素原子、C1-C10的取代或未取代的烷氧基中的一种；R 1、R 2、R 3、R 4各自独立地选自H、卤素原子或C1-C5的取代或未取代的烃基。采用上述非水电解液制备得到的二次电池特别适用于高温条件下的工作，提高了二次电池的环境适应性。

Description

一种非水电解液及二次电池 技术领域
本发明属于储能电子件技术领域，具体涉及一种非水电解液及二次电池。
背景技术
随着人们对电动汽车和混合电动汽车的性能要求越来越高，动力电池性能尤其是高温性能面临更多的挑战。目前动力电池主要以锂离子电池为主，锂离子电池电芯主要由正极、负极、隔膜以及电解液组成。在锂离子电池充电过程中，电池正极材料中的锂离子脱嵌出来，通过电解液嵌入碳负极中。在初始阶段，电解液成分会优先得电子，在碳负极表面反应产生Li2CO3、Li2O、LiOH等化合物，从而在负极表面形成钝化膜，该钝化膜称为固体电解液界面膜(SEI)。在初始充电过程中形成的SEI膜能够阻止电解液进一步在碳负极表面分解，起到锂离子导体作用，只允许锂离子通过。但是，在后续的锂离子电池的充放电循环过程中，电极可能会发生变化导致SEI膜发生破裂，这可能会致使负极再次暴露在电解液中并持续与电解液发生反应，在消耗电解液的同时产生气体，导致锂离子电池的内压增加，降低电池的循环寿命。电池在高温条件下储存或充电循环使用时，电极体积变化更为明显，SEI膜更容易发生破裂，从而导致锂离子电池在高温条件下的电化学性能下降更为明显。因此，SEI膜的质量严重影响锂离子电池的高温性能。
为了提高锂离子电池的各项性能，许多科研者通过往电解液中添加不同的负极成膜添加剂，例如氟代碳酸乙烯酯、碳酸亚乙烯酯、1,3-丙烷磺酸内酯等添加剂来改善SEI膜的质量，从而改善电池的各项性能。虽然现有的成膜添加剂能够改善电池的某一性能，但改善的程度有限，特别是高温循环性能和存储性能，仍然不能满足市场的需要，如何开发一种能够进一步提高高温循环性能和存储性能的添加剂是亟需解决的问题。
发明内容
针对现有二次电池存在高温循环性能和高温存储性能不足的问题，本发明提供了一种非水电解液及其制备方法。
本发明解决上述技术问题所采用的技术方案如下：
一方面，本发明提供了一种非水电解液，包括非水有机溶剂、电解质盐和添加剂，所述添加剂包括结构式1所示的化合物：
其中，Y选自O、C1-C5的取代或未取代的亚烃基；X为基团中的一种，R5为卤素原子、C1-C10的取代或未取代的烷氧基中的一种；R1、R2、R3、R4各自独立地选自H、卤素原子或C1-C5的取代或未取代的烃基。
可选的，Y选自O或C1-C2的取代或未取代的亚烃基；R5为卤素原子、C1-C10的卤代或非卤代烷氧基中的一种；R1、R2、R3、R4各自独立地选自H、卤素原子、C1-C5的烃基或C1-C5的卤代烃基。
可选的，X为基团中的一种。
可选的，所述结构式1所示的化合物选自以下化合物中的一种或多种：

可选的，以所述非水电解液的总质量为100％计，所述结构式1所示的化合物的质量百分含量为0.01％-5.0％。
可选的，所述电解质盐选自锂盐或钠盐；
所述锂盐选自LiPF6、LiBOB、LiDFOB、LiPO2F2、LiBF4、LiSbF6、LiAsF6、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2、LiClO4、LiAlCl4、LiCF3SO3、Li2B10Cl10、LiSO2F、LiTOP(三草酸磷酸锂)、LiDODFP(二氟二草酸磷酸锂)、LiOTFP(四氟草酸磷酸锂)和低级脂肪族羧酸锂盐中的至少一种。
所述钠盐选自NaPF6、NaClO4、NaAsF6、NaSbF6、NaPOF4、NaPO2F2、NaC4BO8、NaC2BF2O4、NaODFB、NaN(SO2C2F5)2、NaN(SO2CF3)(SO2C4F9)2、NaC(SO2CF3)和Na(C2F5)PF3中的至少一种。
可选的，所述非水有机溶剂包括醚类溶剂、腈类溶剂、碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。
可选的，所述添加剂还包括环状硫酸酯类化合物、磺酸内酯类化合物、环状碳酸酯类化合物、磷酸酯类化合物、硼酸酯类化合物和腈类化合物中的至少一种；
优选的，以所述非水电解液的总质量为100％计，所述添加剂的添加量为0.01％～30％。
可选的，所述环状硫酸酯类化合物选自硫酸乙烯酯、硫酸丙烯酯、甲基硫酸乙烯酯、中的至少一种；
所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,3-丙烯磺酸内酯、中的至少一种；
所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、亚甲基碳酸乙烯酯、氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯或结构式2所示化合物中的至少一种，
所述结构式2中，R21、R22、R23、R24、R25、R26各自独立地选自氢原子、卤素原子、C1-C5基团中的一种；
所述磷酸酯类化合物选自三(三甲基硅烷)磷酸酯、三(三甲基硅烷)亚磷酸酯或结构式3所示化合物中的至少一种：
所述结构式3中，R31、R32、R33各自独立的选自C1-C5的饱和烃基、不饱和烃基、卤代烃基、-Si(CmH2m+1)3，m为1～3的自然数，且R31、R32、R33中至少有一个为不饱和烃基；
所述硼酸酯类化合物选自三(三甲基硅烷)硼酸酯和三(三乙基硅烷)硼酸酯中的至少一种；
所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的一种或多种。
另一方面，本发明提供了一种二次电池，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，发明人发现，加入了结构式1所示的化合物作为添加剂，能够在较小的添加量下对非水电解液在正负极上的成膜起到较大的改善效果，所成型的钝化膜具有较大的柔韧性，稳定性高，阻抗增长相对比较缓慢，提升了正负极材料在长期循环中的性能稳定性，延长了电池的循环寿命，推测是由于结构式1所示的化合物具有不对称的双环结构，其一侧具有七元环的环状硫酸酯结构，另一侧为五元环或六元环结构，在形成钝化模时，结构式1所示的化合物两侧开环后形成了不同链长的结构，其活动空间更大，更利于 形成韧性更好的钝化膜。同时，值得注意的是，相比于现有的一些常规添加剂，该钝化膜在高温下的稳定性尤其优异，因此，采用本申请提供的非水电解液制备得到的电池特别适用于高温条件下的工作，提高了电池的环境适应性。
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。
本发明一实施例提供了一种非水电解液，包括非水有机溶剂、电解质盐和添加剂，所述添加剂包括结构式1所示的化合物：
其中，Y选自O、C1-C5的取代或未取代的亚烃基；X为基团中的一种，R5为卤素原子、C1-C10的取代或未取代的烷氧基中的一种；R1、R2、R3、R4各自独立地选自H、卤素原子或C1-C5的取代或未取代的烃基。
发明人发现，结构式1所示的化合物能够在较小的添加量下对非水电解液在正负极上的成膜起到较大的改善效果，所成型的钝化膜具有较大的柔韧性，稳定性高，阻抗增长相对比较缓慢，提升了正负极材料在长期循环中的性能稳定性，延长了电池的循环寿命，推测是由于结构式1所示的化合物具有不对称的双环结构，其一侧具有七元环的环状硫酸酯结构，另一侧为五元环或六元环结构，在形成钝化模时，结构式1所示的化合物两侧开环后形成了不同链长的结构，其活动空间更大，更利于形成韧性更好的钝化膜。同时，值得注意的是，相比于现有的一些常规添加剂，该钝化膜在高温下的稳定性尤其优异，因此，采用本申请提供的非水电解液制备得到的电池特别适用于高温条件下的工作，提高了电池的环境适应性。
在一些实施例中，Y选自O或亚甲基；R5为卤素原子、C1-C10的卤代或非卤代烷氧基中的一种；R1、R2、R3、R4各自独立地选自H、卤素原子、C1-C5的烃基或C1-C5的卤代烃基。
在一些实施例中，X为基团中的一种。
当X选自时，所述结构式1所示的化合物为环状硫酸酯以及环状羧酸酯、环状碳酸酯、环状磷酸酯中一种的组合双环结构，能够进一步提高钝化膜膜的高温稳定性，推测是由于结构式1所示的化合物能够形成含有硫酸锂的无机组分，同时能够聚合形成含杂原子的有机组分，能够减少气体的产生量，有利于综合不同成膜元素对于钝化膜的影响，得到高温稳定性优异的钝化膜。含有无机组分和有机组分的钝化膜，在原子尺度上更为均匀，既能够提高锂离子传导速率，又能够保护正负极结构，提高电池材料稳定性，更好的隔绝正负极材料与电解液之间的接触，从而降低电池极化，抑制阻抗增长，提高电池的高温性能，延长了电池的循环寿命。
在一些实施例中，所述结构式1所示的化合物选自以下化合物中的一种或多种：

以上仅为本发明优选的部分实施例，不应理解为对本发明的限制。
在一些实施例中，所述结构式1所示的化合物可通过以下方法制备得到：
以结构式1所示的化合物选自双环硫酸酯碳酸酯为例，可通过以下方法制备：采用四元醇与碳酸二甲酯发生酯交换反应得到碳酸多元醇酯，再将碳酸多元醇酯与卤化亚硫酰反应得到双环亚硫酸酯碳酸酯，再将双环亚硫酸酯碳酸酯与氧化剂反应，得到双环硫酸酯碳酸酯，具体反应式如下所示：
以结构式1所示的化合物选自双环硫酸酯为例，可通过以下方法制备：采用四元醇与卤化亚硫酰发生反应得到双环亚硫酸酯，再将双环亚硫酸酯与氧化剂反应，得到双环硫酸酯，具体反应式如下所示：
以结构式1所示的化合物选自双环硫酸酯羧酸酯为例，可通过以下方法制备：采用4,5-二羟基-3-羟甲基-戊酸酸催化脱水制备二羟基内酯，再与二氯亚砜反应成双环亚硫酸酯羧酸酯，再与氧化剂反应，得到双环硫酸酯羧酸酯，具体反应式如下所示：
以结构式1所示的化合物选自双环硫酸酯磷酸酯为例，可通过以下方法制备：采用四元醇碳酸单酯与卤化亚硫酰发生反应得到双环亚硫酸酯碳酸酯，再水解得到二羟基亚硫酸酯，进一步与甲基磷酰氯反应，得到双环亚硫酸酯磷酸酯，再与氧化剂反应，得到双环硫酸酯磷酸酯，具体反应式如下所示：
在一些实施例中，以所述非水电解液的总质量为100％计，所述结构式1所示的化合物的质量百分含量为0.01％-5.0％。
具体的，以所述非水电解液的总质量为100％计，所述结构式1所示的化合物的质量百分含量可以为0.01％、0.02％、0.05％、0.08％、1.0％、1.1％、1.3％、1.5％、1.8％、2.0％、2.3％、 2.7％、3.0％、3.4％、3.7％、3.9％、4.1％、4.4％、4.7％或5.0％。
在优选的实施例中，以所述非水电解液的总质量为100％计，所述结构式1所示的化合物的质量百分含量为0.1％-3.0％。
更优选的，以所述非水电解液的总质量为100％计，所述结构式1所示的化合物的质量百分含量为0.5％-3.0％。
所述非水电解液中，所述结构式1所示的化合物的添加量影响正负极表面钝化膜的质量，当结构式1所示的化合物含量过低时，在正负极表面难以形成完整的钝化膜，对于二次电池的性能提升不明显；当结构式1所示的化合物含量过高时，易导致在正负极表面的成膜厚度过大，增加正负极的截面阻抗，而劣化电池的高温性能。
在一些实施例中，所述非水电解液可应用于不同类型的二次电池。
对应的，所述电解质盐包括锂盐或钠盐中的一种或多种。
当所述非水电解液应用于锂离子电池时，所述电解质盐选自锂盐；当所述非水电解液应用于钠离子电池时，所述电解质盐选自钠盐。
在优选的实施例中，所述电解质盐选自锂盐或钠盐。
在优选实施例中，所述锂盐选自LiPF6、LiBOB、LiDFOB、LiPO2F2、LiBF4、LiSbF6、LiAsF6、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2、LiClO4、LiAlCl4、LiCF3SO3、Li2B10Cl10、LiSO2F、LiTOP(三草酸磷酸锂)、LiDODFP(二氟二草酸磷酸锂)、LiOTFP(四氟草酸磷酸锂)和低级脂肪族羧酸锂盐中的至少一种。
在优选实施例中，所述钠盐选自NaPF6、NaClO4、NaAsF6、NaSbF6、NaPOF4、NaPO2F2、NaC4BO8、NaC2BF2O4、NaODFB、NaN(SO2C2F5)2、NaN(SO2CF3)(SO2C4F9)2、NaC(SO2CF3)和Na(C2F5)PF3中的至少一种。
在一些实施例中，所述非水电解液中，所述锂盐的浓度为0.1mol/L～8mol/L。在优选实施例中，所述非水电解液中，所述锂盐的浓度为0.5mol/L～2.5mol/L。具体的，所述非水电解液中，所述锂盐的浓度可以为0.5mol/L、1mol/L、1.5mol/L、2mol/L、2.5mol/L。
在一些实施例中，所述非水电解液中，所述钠盐的浓度为0.1mol/L～2mol/L。在优选实施例中，所述非水电解液中，所述钠盐的浓度为0.4mol/L～1.5mol/L。具体的，所述非水电解液中，所述钠盐的浓度可以为0.1mol/L、0.4mol/L、0.5mol/L、0.7mol/L、0.8mol/L、0.9mol/L、1mol/L、1.2mol/L、1.5mol/L、2mol/L。
在一些实施例中，所述非水有机溶剂包括醚类溶剂、腈类溶剂、碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。
在一些实施例中，醚类溶剂包括环状醚或链状醚，优选为碳原子数3～10的链状醚及碳原子数3～6的环状醚，环状醚具体可以但不限于是1,3-二氧戊烷(DOL)、1,4-二氧惡烷(DX)、冠醚、四氢呋喃(THF)、2-甲基四氢呋喃(2-CH3-THF)，2-三氟甲基四氢呋喃(2-CF3-THF)中的一种或多种；所述链状醚具体可以但不限于是二甲氧基甲烷、二乙氧基甲烷、乙氧基甲氧基甲烷、乙二醇二正丙基醚、乙二醇二正丁基醚、二乙二醇二甲基醚。由于链状醚与锂离 子的溶剂化能力高、可提高离子解离性，因此特别优选粘性低、可赋予高离子电导率的二甲氧基甲烷、二乙氧基甲烷、乙氧基甲氧基甲烷。醚类化合物可以单独使用一种，也可以以任意的组合及比率组合使用两种以上。醚类化合物的添加量没有特殊限制，在不显著破坏本发明高压实锂离子电池效果的范围内是任意的，在非水溶剂体积比为100％中通常体积比为1％以上、优选体积比为2％以上、更优选体积比为3％以上，另外，通常体积比为30％以下、优选体积比为25％以下、更优选体积比为20％以下。在将两种以上醚类化合物组合使用的情况下，使醚类化合物的总量满足上述范围即可。醚类化合物的添加量在上述的优选范围内时，易于确保由链状醚的锂离子离解度的提高和粘度降低所带来的离子电导率的改善效果。另外，负极活性材料为碳基材料的情况下，可抑制因链状醚与锂离子共同发生共嵌入的现象，因此能够使输入输出特性、充放电速率特性达到适当的范围。
在一些实施例中，腈类溶剂具体可以但不限于是乙腈、戊二腈、丙二腈中的一种或多种。
在一些实施例中，碳酸酯类溶剂包括环状碳酸酯或链状碳酸酯，环状碳酸酯具体可以但不限于是碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(GBL)、碳酸亚丁酯(BC)中的一种或多种；链状碳酸酯具体可以但不限于是碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)中的一种或多种。环状碳酸酯的含量没有特殊限制，在不显著破坏本发明锂离子电池效果的范围内是任意的，但在单独使用一种的情况下其含量的下限相对于非水电解液的溶剂总量来说，通常体积比为3％以上、优选体积比为5％以上。通过设定该范围，可避免由于非水电解液的介电常数降低而导致电导率降低，易于使非水电解质电池的大电流放电特性、相对于负极的稳定性、循环特性达到良好的范围。另外，上限通常体积比为90％以下、优选体积比为85％以下、更优选体积比为80％以下。通过设定该范围，可提高非水电解液的氧化/还原耐性，从而有助于提高高温保存时的稳定性。链状碳酸酯的含量没有特殊限定，相对于非水电解液的溶剂总量，通常为体积比为15％以上、优选体积比为20％以上、更优选体积比为25％以上。另外，通常体积比为90％以下、优选体积比为85％以下、更优选体积比为80％以下。通过使链状碳酸酯的含量在上述范围，容易使非水电解液的粘度达到适当范围，抑制离子电导率的降低，进而有助于使非水电解质电池的输出特性达到良好的范围。在组合使用两种以上链状碳酸酯的情况下，使链状碳酸酯的总量满足上述范围即可。
在一些实施例中，还可优选使用具有氟原子的链状碳酸酯类(以下简称为“氟化链状碳酸酯”)。氟化链状碳酸酯所具有的氟原子的个数只要为1以上则没有特殊限制，但通常为6以下、优选4以下。氟化链状碳酸酯具有多个氟原子的情况下，这些氟原子相互可以键合于同一个碳上，也可以键合于不同的碳上。作为氟化链状碳酸酯，可列举，氟化碳酸二甲酯衍生物、氟化碳酸甲乙酯衍生物、氟化碳酸二乙酯衍生物等。
羧酸酯类溶剂包括环状羧酸酯和/或链状碳酸酯。作为环状羧酸酯的例子，可以列举如：γ-丁内酯、γ-戊内酯、δ-戊内酯中的一种或多种。作为链状碳酸酯的例子，可以列举如：乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(EP)、乙酸丁酯、丙酸丙酯(PP)、丙酸丁酯中的一种或多种。
在一些实施例中，砜类溶剂包括环状砜和链状砜，优选地，在为环状砜的情况下，通常为碳原子数3～6、优选碳原子数3～5，在为链状砜的情况下，通常为碳原子数2～6、优选碳原子数2～5的化合物。砜类溶剂的添加量没有特殊限制，在不显著破坏本发明锂离子电池效果 的范围内是任意的，相对于非水电解液的溶剂总量，通常体积比为0.3％以上、优选体积比为0.5％以上、更优选体积比为1％以上，另外，通常体积比为40％以下、优选体积比为35％以下、更优选体积比为30％以下。在组合使用两种以上砜类溶剂的情况下，使砜类溶剂的总量满足上述范围即可。砜类溶剂的添加量在上述范围内时，倾向于获得高温保存稳定性优异的电解液。
在优选的实施例中，所述溶剂为环状碳酸酯和链状碳酸酯的混合物。
在一些实施例中，所述添加剂还包括环状硫酸酯类化合物、磺酸内酯类化合物、环状碳酸酯类化合物、磷酸酯类化合物、硼酸酯类化合物和腈类化合物中的至少一种；
优选的，以所述非水电解液的总质量为100％计，所述添加剂的添加量为0.01％～30％。
优选的，所述环状硫酸酯类化合物选自硫酸乙烯酯、硫酸丙烯酯、甲基硫酸乙烯酯、中的至少一种。
所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,3-丙烯磺酸内酯、中的至少一种；
所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、亚甲基碳酸乙烯酯、氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯或结构式2所示化合物中的至少一种，
所述结构式2中，R21、R22、R23、R24、R25、R26各自独立地选自氢原子、卤素原子、C1-C5基团中的一种。具体的，所述结构式2所示的化合物包括 中的至少一种。
所述磷酸酯类化合物选自三(三甲基硅烷)磷酸酯、三(三甲基硅烷)亚磷酸酯或结构式3所示化合物中的至少一种：
所述结构式3中，R31、R32、R33各自独立的选自C1-C5的饱和烃基、不饱和烃基、卤代烃基、-Si(CmH2m+1)3，m为1～3的自然数，且R31、R32、R33中至少有一个为不饱和烃基；
在优选的实施例中，所述磷酸酯类化合物可为磷酸三炔丙酯、二炔丙基甲基磷酸酯、二炔丙基乙基磷酸酯、二炔丙基丙基磷酸酯、二炔丙基三氟甲基磷酸酯、二炔丙基-2,2,2-三氟乙基磷酸酯、二炔丙基-3,3,3-三氟丙基磷酸酯、二炔丙基六氟异丙基磷酸酯、磷酸三烯丙酯、二烯丙基甲基磷酸酯、二烯丙基乙基磷酸酯、二烯丙基丙基磷酸酯、二烯丙基三氟甲基磷酸酯、二烯丙基-2,2,2-三氟乙基磷酸酯、二烯丙基-3,3,3-三氟丙基磷酸酯、二烯丙基六氟异丙基磷酸酯中的至少一种；
所述硼酸酯类化合物选自三(三甲基硅烷)硼酸酯和三(三乙基硅烷)硼酸酯中的至少一种；
所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的一种或多种。
在另一些实施例中，所述添加剂还可包括其它能改善电池性能的添加剂：例如，提升电池安全性能的添加剂，具体如氟代磷酸酯、环磷腈等阻燃添加剂，或叔戊基苯、叔丁基苯等防过充添加剂。
需要说明的是，除非特殊说明，一般情况下，所述添加剂中任意一种可选物质在非水电解液中的添加量为10％以下，优选的，添加量为0.1-5％，更优选的，添加量为0.1％～2％。具体的，所述添加剂中任意一种可选物质的添加量可以为0.05％、0.08％、0.1％、0.5％、0.8％、1％、1.2％、1.5％、1.8％、2％、2.2％、2.5％、2.8％、3％、3.2％、3.5％、3.8％、4％、4.5％、5％、5.5％、6％、6.5％、7％、7.5％、7.8％、8％、8.5％、9％、9.5％、10％。
在一些实施例中，当添加剂选自氟代碳酸乙烯酯时，以所述非水电解液的总质量为100％计，所述氟代碳酸乙烯酯的添加量为0.05％～30％。
本发明的另一实施例提供了一种二次电池，包括正极、负极以及如上所述的非水电解液。
在一些实施例中，所述正极包括正极材料层和正极集流体，所述正极材料层形成于所述正极集流体的表面。
所述正极集流体选自可传导电子的金属材料，优选的，所述正极集流体包括Al、Ni、锡、铜、不锈钢的一种或多种，在更优选的实施例中，所述正极集流体选自铝箔。
所述正极材料层包括正极活性材料、正极粘结剂和正极导电剂。
所述正极粘结剂包括聚偏氟乙烯、偏氟乙烯的共聚物、聚四氟乙烯、偏氟乙烯-六氟丙烯的共聚物、四氟乙烯-六氟丙烯的共聚物、四氟乙烯-全氟烷基乙烯基醚的共聚物、乙烯-四氟乙烯的共聚物、偏氟乙烯-四氟乙烯的共聚物、偏氟乙烯-三氟乙烯的共聚物、偏氟乙烯-三氯乙烯的共聚物、偏氟乙烯-氟代乙烯的共聚物、偏氟乙烯-六氟丙烯-四氟乙烯的共聚物、热塑性聚酰亚胺、聚乙烯及聚丙烯等热塑性树脂；丙烯酸类树脂；羟甲基纤维素钠；以及苯乙烯丁二烯橡胶中的一种或多种。
所述正极导电剂包括导电炭黑、导电碳球、导电石墨、导电碳纤维、碳纳米管、石墨烯或还原氧化石墨烯中的一种或多种。
在一些实施例中，所述正极包括含有正极活性材料的正极材料层，所述正极活性材料的种类没有特别限制，可以根据实际需求进行选择，只要是能够可逆地嵌入/脱嵌金属离子(锂离子或钠离子)的正极活性材料或转换型正极材料即可。
在优选实施例中，所述电池为锂离子电池，其正极活性材料可选自LiFe1-x’M’x’PO4、LiMn2-y’My’O4和LiNixCoyMnzM1-x-y-zO2中的一种或多种，其中，M’选自Mn、Mg、Co、Ni、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V或Ti中的一种或多种，M选自Fe、Co、Ni、Mn、Mg、Cu、Zn、Al、Sn、B、Ga、Cr、Sr、V或Ti中的一种或多种，且0≤x’＜1，0≤y’≤1，0≤y≤1，0≤x≤1，0≤z≤1，x+y+z≤1，所述正极活性材料还可以选自硫化物、硒化物、卤化物中的一种或几种。更为优选的，所述正极活性材料可选自LiCoO2、LiFePO4、LiFe0.8Mn0.2PO4、LiNi0.5Co0.2Mn0.3O2、LiNi0.6Co0.2Mn0.2O2、LiNi0.8Co0.1Mn0.1O2、LiNi0.5Co0.2Mn0.2Al0.1O2、LiMn2O4、LiNi0.5Co0.2Al0.3O2中的一种或多种。
在优选实施例中，所述电池为钠离子电池，其正极活性材料可选自过镀金属氧化物、过镀金属硫化物、磷基材料、磷酸盐材料、硫酸盐材料、钛酸盐材料、普鲁士蓝类材料中的一种或几种。所述过镀金属氧化物和所述过镀金属硫化物的化学式为M1xNy，M1可选自Fe、Co、Ni、Cu、Mn、Sn、Mo、Sb、V中的一种或几种，N选自O或S，更为优选的，所述过渡金属氧化物为NaNimFenMnpO2(m+n+p＝1，0≤m≤1，0≤n≤1，0≤p≤1)或NaNimConMnpO2(m+n+p＝1，0≤m≤1，0≤n≤1，0≤p≤1)，所述磷基材料可选自红磷、白磷、黑磷中的一种或几种，所述磷酸盐的化学式为Na3(MO1-xPO4)2F1+2x，0≤x≤1，M选自Al、V、Ge、Fe、Ga中的至少一种，更为优选的，所述磷酸盐为Na3(VPO4)2F3或Na3(VOPO4)2F；和/或所述磷酸盐的化学式为Na2MPO4F，M选自Fe、Mn中的至少一种，更为优选的，所述磷酸盐为Na2FePO4F或Na2MnPO4F；所述硫酸盐的化学式为Na2M(SO4)2·2H2O，M可选自Cr、Fe、Co、Ni、Cu、Mn、Sn、Mo、Sb、V中的至少一种；所述钛酸盐材料可选自Na2Ti3O7、Na2Ti6O13、 Na4Ti5O12、Li4Ti5O12、NaTi2(PO4)3中的至少一种；所述普鲁士蓝类材料的分子式为NaxM[M′(CN)6]y·zH2O，其中，M为过渡金属，M′为过渡金属，0<x≤2，0.8≤y<1，0<z≤20，更为优选的，所述普鲁士蓝类材料为NaxMn[Fe(CN)6]y·nH2O(0＜x≤2，0＜y≤1，0＜z≤10)或NaxFe[Fe(CN)6]y·nH2O(0＜x≤2，0＜y≤1，0＜z≤10)。
在一些实施例中，所述负极包括负极材料层，所述负极材料层包括负极活性材料。
在优选实施例中，当所述二次电池为锂离子电池时，其负极活性材料包括碳基负极、硅基负极、锡基负极、锂负极中的至少一种。其中碳基负极可包括石墨、硬碳、软碳、石墨烯、中间相碳微球等；硅基负极可包括硅材料、硅的氧化物、硅碳复合材料以及硅合金材料等；锡基负极可包括锡、锡碳、锡氧、锡金属化合物；锂负极可包括金属锂或锂合金。锂合金具体可以是锂硅合金、锂钠合金、锂钾合金、锂铝合金、锂锡合金和锂铟合金中的至少一种。
在优选实施例中，当所述二次电池为钠离子电池时，其负极活性材料包括金属钠、石墨、软碳、硬碳、碳纤维、中间相碳微球、硅基材料、锡基材料、钛酸锂或其他能与钠形成合金材料的金属等中的至少一种。其中，所述合金材料还可选自由Si、Ge、Sn、Pb、Sb中的至少一种与C组成的合金材料，所述石墨可选自人造石墨、天然石墨以及改性石墨中的至少一种；所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅合金中的至少一种；所述锡基材料可选自单质锡、锡氧化合物、锡合金中的至少一种。
在一些实施例中，所述负极材料层还包括有负极粘结剂和负极导电剂，所述负极活性材料、所述负极粘结剂和所述负极导电剂共混得到所述负极材料层。
所述负极粘接剂和负极导电剂的可选择范围分别与所述正极粘结剂和正极导电剂相同，在此不再赘述。
在一些实施例中，所述负极还包括负极集流体，所述负极材料层形成于所述负极集流体的表面。
所述负极集流体选自可传导电子的金属材料，优选的，所述负极集流体包括Al、Ni、锡、铜、不锈钢的一种或多种，在更优选的实施例中，所述负极集流体选自铜箔。
在一些实施例中，所述锂离子电池中还包括有隔膜，所述隔膜位于所述正极片和所述负极片之间。
所述隔膜可为现有常规隔膜，可以是聚合物隔膜、无纺布等，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。
以下实施例和对比例涉及的化合物如下表所示：
表1
实施例1
本实施例以制备锂离子电池为例对本发明进行说明，包括以下操作步骤：
1)非水电解液的制备：
将碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸甲乙酯(EMC)按质量比为EC:DEC:EMC＝1:1:1进行混合，然后加入六氟磷酸锂(LiPF6)至摩尔浓度为1mol/L，以非水电解液的总重量为100％计，加入如表2中实施例1所示质量百分含量的化合物1。
2)正极板的制备：
按93:4:3的质量比混合正极活性材料锂镍钴锰氧化物LiNi0.5Co0.2Mn0.3O2，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之间。
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之间。
4)电芯的制备：
在正极板和负极板之间放置厚度为20μm的三层隔膜，然后将正极板、负极板和隔膜组成的三明治结构进行卷绕，再将卷绕体压扁后放入铝箔包装袋，在75℃下真空烘烤48h，得到待注液的电芯。
5)电芯的注液和化成：
在露点控制在-40℃以下的手套箱中，将上述制备的电解液注入电芯中，经真空封装，静止24h。
然后按以下步骤进行首次充电的常规化成：0.05C恒流充电180min，0.2C恒流充电至3.95V，二次真空封口，然后进一步以0.2C的电流恒流充电至4.2V，常温搁置24h后，以0.2C的电流恒流放电至3.0V，得到一种LiNi0.5Co0.2Mn0.3O2/人造石墨锂离子电池。
实施例2～16
实施例2～16用于说明本发明公开的锂离子电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
采用表2中实施例2～16所示的添加剂及添加量。
对比例1～6
对比例1～6用于对比说明本发明公开的锂离子电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
采用表2中对比例1～6所示的添加剂及添加量。
性能测试
对上述制备得到的锂离子电池进行如下性能测试：
(1)高温循环性能测试
将锂离子电池置于恒温45℃的烘箱中，以1C的电流恒流充电至4.2V(LiNi0.5Co0.2Mn0.3O2/人造石墨锂离子电池)，再恒压充电至电流下降至0.02C，然后以1C的电流恒流放电至3.0V，如此循环，记录第1次的放电容量和最后一次的放电容量。
按下式计算循环的容量保持率：
电池容量保持率(％)＝最后一次的放电容量/第1次的放电容量×100％。
(2)高温储存性能测试
将锂离子电池化成后在常温下用1C恒流恒压充至4.2V(LiNi0.5Co0.2Mn0.3O2/人造石墨锂离子电池)，测量电池初始放电容量及初始电池厚度，然后在60℃环境中储存30天后，以1C放电至3.0V，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％；
体积膨胀率(％)＝(储存后电池厚度-初始电池厚度)/初始电池厚度×100％。
测试结果如表2所示。
表2

从实施例1～7和对比例1的测试结果可以看出，相比于不添加结构式1所示化合物的非水电解液，在非水电解液中添加结构式1所示的化合物作为添加剂，能够有效改善锂离子电池的高温循环容量保持率、高温存储的容量保持率、容量恢复率和体积膨胀率，说明由结构式1所示的化合物在正负极表面分解形成的钝化膜具有较高的高温稳定性，提升了正负极材料在长期循环中的性能稳定性，提高了锂离子电池在高温下的循环性能和存储性能。从实施例1～7的测试结果可知，随着结构式1所示的化合物的含量提升，锂离子电池的高温存储性能和高温循环性能先提升后降低，尤其是，当化合物的含量为0.5％-3.0％时，锂离子电池具有最佳的综合性能，说明在锂离子电池充放电循环的过程中，电解液中结构式1所示的化合物的含量为0.5％-3.0％时，能够保证所形成的SEI膜薄厚适中，稳定性更好。
由实施例4和对比例2～6的测试结果可以看出，相比于常规成膜添加剂及其组合，如碳 酸亚乙烯酯(VC)、硫酸乙烯酯(DTD)、氟代碳酸乙烯酯(FEC)和1,3丙烷磺酸内酯(PS)，采用本申请提供的结构式1所示的化合物作为添加剂，能够更加显著地改善锂离子电池在高温下的存储性能和循环性能，降低电池膨胀率，说明相比于常规成膜添加剂，由结构式1所示化合物形成的钝化膜具有更加优异的高温稳定性。
由实施例4、8～12的测试结果可以看出，采用不同结构式1所示的化合物作为非水电解液的添加剂时，对于锂离子电池的高温存储性能和高温循环性能均有一定程度的提高。
由实施例4、13～16的测试结果可以看出，采用碳酸亚乙烯酯(VC)、硫酸乙烯酯(DTD)、氟代碳酸乙烯酯(FEC)或1,3丙烷磺酸内酯(PS)与结构式1所示的化合物进行配合，能够更加明显地提高锂离子电池的高温循环性能，推测是由于碳酸亚乙烯酯(VC)、硫酸乙烯酯(DTD)、氟代碳酸乙烯酯(FEC)或1,3丙烷磺酸内酯(PS)与结构式1所示的化合物共同参与正负极表面钝化膜的成型，利于提高钝化膜的质量。
实施例17
本实施例以制备钠离子电池为例对本发明进行说明，包括以下操作步骤：
1)非水电解液的制备：
将碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸甲乙酯(EMC)按质量比为EC:DEC:EMC＝1:1:1进行混合，然后加入六氟磷酸钠(NaPF6)至摩尔浓度为1mol/L，以所述非水电解液的总重量为100％计，加入如表3中实施例15所示质量百分含量的化合物1。
2)正极片的制备：
按94:3:3的质量比混合正极活性材料Na3V2(PO4)3、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或镍制引出线后得到正极片，其厚度在80-200μm之间。
3)负极片的制备：
按97:1:1:1的质量比混合负极活性材料球形硬碳、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或镍制引出线后得到负极片，其厚度在80-300μm之间。
4)将正极片、隔膜、负极片按顺序叠好，经铝塑膜封装、再烘烤、注液、静置、化成、夹具整形、二封、容量测试，完成钠离子电池的制备。
实施例18～33
实施例18～33用于说明本发明公开的钠离子电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
采用表3中实施例18～33所示的添加剂及添加量。
对比例7～10
对比例7～10用于对比说明本发明公开的钠离子电池及其制备方法，包括实施例1中大部分操作步骤，其不同之处在于：
采用表3中对比例7～10所示的添加剂及添加量。
性能测试
对上述制备得到的钠离子电池进行如下性能测试：
(1)高温循环性能测试
将化成后的钠离子电池在45℃静置2h，以0.5C的倍率恒流充电至4.0V，再恒压充电至电流为0.03C，然后以1C的电流恒流放电至1.5V，循环200周。
测量电池初始放电容量D1、循环200周的放电容量D2，电池库伦效率E。
电池容量保持率(％)＝容量D2/初始容量D1×100％。
(2)高温储存性能测试
将化成后的钠离子电池在常温下以0.5C的电流恒流充电至4.0V，再恒压充电至电流下降至0.03C，然后以1C的电流恒流放电至1.5V，测量电池初始放电容量D1、初始电池体积V1及初始阻抗F1，然后充至满电在60℃环境中储存30天后，以1C放电至3V，测量电池的保持容量D2、恢复容量D3、储存后阻抗F2及储存后电池体积V2。计算公式如下：
电池容量保持率(％)＝保持容量D2/初始容量D1×100％；
电池容量恢复率(％)＝恢复容量D3/初始容量D1×100％；
体积膨胀率(％)＝(储存后电池体积V2-初始电池体积V1)/初始电池体积V1×100％；
测试结果如表3所示。
表3

从实施例17～27和对比例7的测试结果可以看出，与结构式1所示化合物在锂离子电池中所起的作用相似，在钠离子电池的非水电解液中加入结构式1所示化合物，同样能够起到改善钠离子电池的高温循环容量保持率、高温存储的容量保持率、容量恢复率和体积膨胀率的作用，说明由结构式1所示的化合物在正负极表面分解形成的钝化膜具有较高的高温稳定性，提升了正负极材料在长期循环中的性能稳定性，提高了钠离子电池在高温下的循环性能和存储性能。从实施例17～27的测试结果可知，随着结构式1所示的化合物的含量提升，钠离子电池的高温存储性能和高温循环性能先提升后降低，尤其是，当化合物的含量为0.5％～5％时，钠离子电池具有最佳的综合性能，说明在钠离子电池充放电循环的过程中，电解液中结构式1所示的化合物的含量为0.5％～5％时，能够保证所形成的SEI膜薄厚适中，稳定性更好。
由实施例20和对比例8～10的测试结果可以看出，相比于常规成膜添加剂及其组合，如碳酸亚乙烯酯(VC)、硫酸乙烯酯(DTD)和氟代碳酸乙烯酯(FEC)，采用本申请提供的结构式1所示的化合物作为添加剂，能够更加显著地改善钠离子电池在高温下的存储性能和循环性能，降低电池膨胀率，说明相比于常规成膜添加剂，由结构式1所示化合物形成的钝化膜具有更加优异的高温稳定性。
由实施例20、25～27的测试结果可以看出，采用碳酸亚乙烯酯(VC)、硫酸乙烯酯(DTD)或氟代碳酸乙烯酯(FEC)与结构式1所示的化合物进行配合，能够更加明显地提高钠离子电池的高温循环性能，推测是由于碳酸亚乙烯酯(VC)、硫酸乙烯酯(DTD)或氟代碳酸乙烯酯(FEC)与结构式1所示的化合物共同参与正负极表面钝化膜的成型，利于提高钝化膜的质量。
由实施例20、28～32的测试结果可以看出，采用不同结构式1所示的化合物作为非水电解液的添加剂时，对于钠离子电池的高温存储性能和高温循环性能均有一定程度的提高。
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 (18)

  1. 一种非水电解液，其特征在于，包括非水有机溶剂、电解质盐和添加剂，所述添加剂包括结构式1所示的化合物：
    其中，Y选自O、C1-C5的取代或未取代的亚烃基；X为基团中的一种，R5为卤素原子、C1-C10的取代或未取代的烷氧基中的一种；R1、R2、R3、R4各自独立地选自H、卤素原子或C1-C5的取代或未取代的烃基。
  2. 根据权利要求1所述的非水电解液，其特征在于，Y选自O或C1-C2的取代或未取代的亚烃基；R5为卤素原子、C1-C10的卤代或非卤代烷氧基中的一种；R1、R2、R3、R4各自独立地选自H、卤素原子、C1-C5的烃基或C1-C5的卤代烃基。
  3. 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1所示的化合物选自以下化合物中的一种或多种：

  4. 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，所述结构式1所示的化合物的质量百分含量为0.01％-5.0％。
  5. 根据权利要求1所述的非水电解液，其特征在于，所述电解质盐选自锂盐或钠盐。
  6. 根据权利要求5所述的非水电解液，其特征在于，所述锂盐选自LiPF6、LiBOB、LiDFOB、LiPO2F2、LiBF4、LiSbF6、LiAsF6、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2、LiClO4、LiAlCl4、LiCF3SO3、Li2B10Cl10、LiSO2F、LiTOP(三草酸磷酸锂)、LiDODFP(二氟二草酸磷酸锂)、LiOTFP(四氟草酸磷酸锂)和低级脂肪族羧酸锂盐中的至少一种。
  7. 根据权利要求5所述的非水电解液，其特征在于，所述钠盐选自NaPF6、NaClO4、NaAsF6、NaSbF6、NaPOF4、NaPO2F2、NaC4BO8、NaC2BF2O4、NaODFB、NaN(SO2C2F5)2、NaN(SO2CF3)(SO2C4F9)2、NaC(SO2CF3)和Na(C2F5)PF3中的至少一种。
  8. 根据权利要求1所述的非水电解液，其特征在于，所述非水有机溶剂包括醚类溶剂、腈类溶剂、碳酸酯类溶剂和羧酸酯类溶剂中的一种或多种。
  9. 根据权利要求1所述的非水电解液，其特征在于，所述添加剂还包括环状硫酸酯类化合物、磺酸内酯类化合物、环状碳酸酯类化合物、磷酸酯类化合物、硼酸酯类化合物和腈类 化合物中的至少一种。
  10. 根据权利要求9所述的非水电解液，其特征在于，以所述非水电解液的总质量为100％计，所述添加剂的添加量为0.01％～30％。
  11. 根据权利要求9所述的非水电解液，其特征在于，所述环状硫酸酯类化合物选自硫酸乙烯酯、硫酸丙烯酯、甲基硫酸乙烯酯、 中的至少一种。
  12. 根据权利要求9所述的非水电解液，其特征在于，所述磺酸内酯类化合物选自1,3-丙烷磺酸内酯、1,4-丁烷磺酸内酯、1,3-丙烯磺酸内酯、中的至少一种。
  13. 根据权利要求9所述的非水电解液，其特征在于，所述环状碳酸酯类化合物选自碳酸亚乙烯酯、碳酸乙烯亚乙酯、亚甲基碳酸乙烯酯、氟代碳酸乙烯酯、三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯或结构式2所示化合物中的至少一种，
    所述结构式2中，R21、R22、R23、R24、R25、R26各自独立地选自氢原子、卤素原子、C1-C5基团中的一种。
  14. 根据权利要求9所述的非水电解液，其特征在于，所述磷酸酯类化合物选自三(三甲基硅烷)磷酸酯、三(三甲基硅烷)亚磷酸酯或结构式3所示化合物中的至少一种：
    所述结构式3中，R31、R32、R33各自独立的选自C1-C5的饱和烃基、不饱和烃基、卤代烃基、-Si(CmH2m+1)3，m为1～3的自然数，且R31、R32、R33中至少有一个为不饱和烃基。
  15. 根据权利要求9所述的非水电解液，其特征在于，所述硼酸酯类化合物选自三(三甲基硅烷)硼酸酯和三(三乙基硅烷)硼酸酯中的至少一种。
  16. 根据权利要求9所述的非水电解液，其特征在于，所述腈类化合物选自丁二腈、戊二腈、乙二醇双(丙腈)醚、己烷三腈、己二腈、庚二腈、辛二腈、壬二腈、癸二腈中的一种或多种。
  17. 一种二次电池，其特征在于，包括正极、负极以及如权利要求1～16任意一项所述的非水电解液。
  18. 根据权利要求17所述的二次电池，其特征在于，所述二次电池为锂金属电池、锂离子电池或钠离子电池。
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