Additive for secondary battery, non-aqueous electrolyte for secondary battery and secondary battery
By using diester compounds and boron oxalate-containing non-aqueous electrolytes in secondary batteries, a stable solid electrolyte interface film is formed, which solves the problem of gas swelling in secondary batteries at high temperatures and improves high and low temperature cycling and storage performance.
Patent Information
- Application Number
- CN202410572946.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-10
- Publication Date
- 2025-11-11
AI Technical Summary
Existing secondary batteries are prone to gas generation and swelling at high temperatures, and their cycle performance and storage performance are insufficient in high and low temperature environments.
A non-aqueous electrolyte containing diester compounds and boron oxalate is used to form a stable solid electrolyte interface film on the electrode surface, thereby reducing battery impedance, suppressing side reactions, and improving ion conductivity and interface stability.
It significantly improves the high and low temperature cycle performance and storage performance of secondary batteries, reduces battery impedance, and enhances the overall performance of the battery.
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Figure CN120933464A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrolytes, and in particular to a lithium / sodium ion battery electrolyte that combines good high and low temperature cycling performance and storage performance, and its application in secondary batteries. Background Technology
[0002] In recent years, rechargeable batteries have attracted much attention due to their widespread application in next-generation information and communication, electric vehicles, energy storage power stations, and the energy internet. Research and technological development of rechargeable batteries are continuously deepening to meet the demands of their widespread application in various fields. Ideal characteristics of rechargeable batteries include high specific energy, long cycle life, high safety, high power, and low cost; these are key factors affecting the overall performance of rechargeable batteries. As the medium for ion transport during battery charging and discharging, the electrolyte has a decisive influence on battery performance, especially in terms of rate performance, high and low temperature performance, cycle stability, and storage performance. Therefore, developing a non-aqueous electrolyte with excellent overall performance, enabling rapid charging, stable cycling, and long-term storage, is crucial for the future development of rechargeable batteries.
[0003] Researchers in this invention have discovered through experiments that constructing a stable and low-impedance solid electrolyte interphase (SEI) film at the electrode-solution interface can significantly improve the cycle performance, rate performance, and storage performance of secondary batteries. Studies have shown that common compounds containing oxalic acid functional groups have excellent film-forming effects, forming stable organic-phase-rich SEI films with low resistance and high ionic conductivity, while also reducing side reactions between the electrode and electrolyte. However, compounds containing oxalic acid functional groups often face challenges such as increased gas production and significant DCIR impedance growth during later battery storage. GC gas analysis revealed that oxalate additives easily generate gases such as CO2 under high temperature and pressure conditions, leading to problems such as bulging of pouch batteries. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention proposes an additive for secondary batteries, a non-aqueous electrolyte for secondary batteries, and a secondary battery thereof, enabling the secondary battery to simultaneously achieve good high and low temperature cycling performance and storage performance.
[0005] The objective of this invention is achieved through the following technical solution:
[0006] A secondary battery electrolyte comprises an electrolyte salt, a non-aqueous solvent, and an additive, said additive comprising at least one diester compound represented by structural formula (I):
[0007]
[0008] In formula (I), R1 is a halogen, a substituted or unsubstituted C1-C6 alkyl, a substituted or unsubstituted C3-C9 cycloalkyl, or a substituted or unsubstituted C6-C18 aryl; R2 is a substituted or unsubstituted C1-C6 alkylene, a substituted or unsubstituted C2-C6 alkenyl, a substituted or unsubstituted C2-C6 alkyne, or a substituted or unsubstituted C6-C18 aryl; R3 is a halogen, a substituted or unsubstituted C1-C6 alkyl, a substituted or unsubstituted C2-C6 alkenyl, a substituted or unsubstituted C2-C6 alkyne, a substituted or unsubstituted C3-C7 cycloalkyl, a substituted or unsubstituted C3-C7 cycloalkenyl, or a substituted or unsubstituted C6-C18 aryl; X is -OC(=O)O-, -OS(=O)2O-, -OS(=O)O-, -S(=O)O-, or -OS(=O)-.
[0009] Preferably, in the diester compound, R1 is a halogen, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C3-C7 cycloalkyl group, or a substituted or unsubstituted C6-C12 aryl group; R2 is a substituted or unsubstituted C1-C3 alkylene group, a substituted or unsubstituted C2-C4 alkenylene group, a substituted or unsubstituted C2-C4 alkyneene group, or a substituted or unsubstituted C6-C12 aryl group; and R3 is a halogen, a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C2-C4 alkenylene group, a substituted or unsubstituted C2-C4 alkyne group, or a substituted or unsubstituted C6-C12 aryl group.
[0010] More preferably, the diester compound is selected from at least one of the compounds with the following structures:
[0011]
[0012]
[0013] Compound (I-1) is prepared by reacting chloroformate and ethylene glycol to obtain an alkyl hydroxyethyl carbonate intermediate, which is then reacted with chloroxalate. The specific reaction route is shown below:
[0014]
[0015] In the above-mentioned secondary battery electrolyte, the amount of diester compound in the electrolyte is 0.001 to 3.0 wt% of the total mass of the electrolyte.
[0016] Furthermore, in the secondary battery electrolyte, the diester compound is preferably used in an amount of 0.01 to 2.0 wt% of the total mass of the electrolyte.
[0017] Furthermore, the secondary battery electrolyte also contains boron oxalate, with an amount accounting for 0.01 to 10.0 wt% of the total mass of the electrolyte.
[0018] Furthermore, in the secondary battery electrolyte, the boron oxalate is preferably at least one of LiDFOB, LiBOB, NaDFOB, or NaBOB, and its amount accounts for 0.1 to 5.0 wt% of the total mass of the electrolyte.
[0019] The diester compound of this invention serves as an excellent film-forming additive. One end of the oxalic acid group is attached to a saturated alkyl substituent, which, compared to unsaturated groups such as alkenyl and alkynyl substituents, can reduce battery impedance. The other end is attached to substituents containing unsaturated ester groups such as carbonates, sulfates, and sulfonates, which can preferentially oxidize and decompose on the surface of the positive electrode to form a stable solid electrolyte interface film. Simultaneously, during charging, it undergoes reduction on the surface of the negative electrode to generate a component rich in organic matter with high ionic conductivity, thereby improving ion conduction performance, inhibiting electrolyte decomposition, reducing the content of inorganic lithium salts in the interface film, and thus reducing battery impedance and improving battery cycle performance.
[0020] Boron-containing oxalates have excellent film-forming properties, enabling them to form inorganic B- and O-rich interfacial layers on electrode surfaces. This inhibits the dissolution of transition metal ions, provides rapid ion diffusion channels, enhances interfacial stability, and reduces the occurrence of side reactions.
[0021] Furthermore, in the secondary battery electrolyte, the electrolyte salt is selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluorooxalate phosphate, lithium tri(oxalate) phosphate, lithium difluorobis(oxalate) phosphate, sodium hexafluorophosphate, sodium tetrafluoroborate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, and sodium difluorophosphate.
[0022] Furthermore, in the secondary battery electrolyte, the non-aqueous solvent is selected from at least one of C3-C6 carbonate or fluorocarbonate compounds, C3-C8 carboxylic acid esters or fluorocarboxylic acid ester compounds, sulfone compounds or ether compounds.
[0023] Preferably, the C3-C6 carbonate or fluorocarbonate compound is selected from at least one of ethylene carbonate, propylene carbonate, butene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, or ethyl propyl carbonate; the C3-C8 carboxylic acid ester or fluorocarboxylic acid ester compound is selected from at least one of γ-butyrolactone, methyl acetate, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, ethyl butyrate, propyl acetate, or propyl propionate; the sulfone compound is selected from at least one of sulfolane, dimethyl sulfoxide, dimethyl sulfone, or diethyl sulfone; and the ether compound is selected from at least one of triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol dimethyl ether, or dioxolane.
[0024] Furthermore, in the secondary battery electrolyte, the additives further include a basic additive selected from at least one of vinylene carbonate, fluoroethylene carbonate, vinyl sulfate, vinyl sulfite, 4,4'-diethylene sulfate, 1,4-dioxane disulfate, tris(trimethylsilyl)phosphate, tris(trimethylsilyl)borate, 1,3-propane sulpholide, 1,3-propene sulpholide, lithium difluorophosphate, adiponitrile, cyclohexylbenzene, lithium difluorosulfonylimide, lithium difluorophosphate, lithium difluorodioxolane phosphate, sodium difluorosulfonylimide, sodium difluorophosphate, and sodium difluorodioxolane phosphate, such that any one basic additive accounts for 0.1 to 5.0 wt% of the total mass of the electrolyte.
[0025] In one specific embodiment, a lithium-ion battery electrolyte is provided, wherein the electrolyte salt is preferably LiPF6, and the amount used accounts for 12.5 wt% of the total mass of the electrolyte; the non-aqueous solvent is preferably at least one of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC), more preferably a mixed solvent of EC, EMC, and DEC, and the mass ratio of the three is EC:EMC:DEC = 3:5:2; the additives include: diester compound and lithium difluorooxalate borate, and the amount used accounts for 0.01 to 2 wt% of the total mass of the electrolyte.
[0026] In another specific embodiment, a sodium-ion battery electrolyte is provided, wherein the electrolyte salt is preferably NaPF6, and the amount used accounts for 14 wt% of the total mass of the electrolyte; the non-aqueous solvent is preferably at least one of diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and propylene carbonate (PC), more preferably a mixed solvent of DEC, EMC, and PC, and the mass ratio of the three is PC:EMC:DEC = 3:5:2; the additives include: diester compound, sodium difluorooxalate borate, and fluoroethylene carbonate, and the amount used accounts for 0.01 to 2 wt% of the total mass of the electrolyte.
[0027] The present invention also provides a lithium / sodium ion secondary battery, comprising a positive electrode, a negative electrode, and a separator, as well as the electrolyte described above.
[0028] Specifically, the positive electrode is selected from at least one of lithium cobalt oxide, lithium iron phosphate, lithium nickel manganese oxide, ternary materials of nickel cobalt manganese lithium, sodium-containing layered oxides, Prussian blue / white, and polyanions (sodium iron phosphate, sodium vanadium phosphate, etc.), and the negative electrode is selected from graphite, silicon-carbon composite materials, lithium titanate, lithium metal, hard carbon, anthracite soft carbon, hard-soft composite carbon, etc.
[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0030] 1. Through the action of diester compounds in the electrolyte of the present invention, an SEI film with excellent ionic conductivity and structural / thermal stability can be formed on the electrode surface, which can effectively reduce the battery interface impedance while suppressing impedance growth during cycling, and further improve the battery cycle performance.
[0031] 2. Based on the addition of diester compounds, this invention introduces boron-containing oxalate, which can not only further suppress the impedance growth during cycling and effectively improve the low-temperature and fast-charging performance of the battery, but also suppress the dissolution of transition metal ions, further improving the high-temperature storage and cycling performance of the battery and improving the overall performance of the battery. Attached Figure Description
[0032] Appendix Figure 1 This is the mass spectrum of the diester compound of structural formula (I-1) of this invention. Detailed Implementation
[0033] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.
[0034] I. Compound Structure Characterization
[0035] Mass spectrometry is an analytical method that performs qualitative and quantitative analysis by measuring the mass-to-charge ratio (m / z) and abundance of ions produced by molecules in a sample. Mass spectrometry can provide information on the molecular structure of compounds and identify the material composition of samples.
[0036] Appendix Figure 1 The mass spectrum of compound (I-1) is given, which contains mass fragments of m / z = 59, 63, 75, 91, 103, 119, 131, 163, and 191, which are consistent with the characteristic fragmented mass fragments of ethylene glycol diester compounds.
[0037] II. Electrolyte Preparation
[0038] Preparation of basic electrolyte 1: In an argon-filled glove box (moisture < 5 ppm, oxygen < 10 ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were uniformly mixed at a mass ratio of EC:EMC:DEC = 3:5:2. Then, lithium hexafluorophosphate (LiPF6) was slowly added to the mixed solution until the molar concentration reached 1.0 mol / L to obtain basic electrolyte 1.
[0039] Preparation of basic electrolyte 2: In an argon-filled glove box (moisture < 5 ppm, oxygen < 10 ppm), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and propylene carbonate (PC) were uniformly mixed at a mass ratio of PC:EMC:DEC = 3:5:2. Then, sodium hexafluorophosphate (NaPF6) was slowly added to the mixed solution until the molar concentration reached 1.0 mol / L to obtain basic electrolyte 2.
[0040] Add the diester compound, boron oxalate, and basic additives quantitatively according to the data in Table 1 below, and mix thoroughly to form an electrolyte:
[0041] Table 1 Electrolyte Formulation
[0042]
[0043]
[0044] Note: After adjusting the amount of additives, only the amount of solvent in the base electrolyte is adjusted, and the distribution ratio of each component in the solvent remains unchanged.
[0045] III. Electrochemical Performance Testing
[0046] The electrolytes from Examples 1-13 and Comparative Examples 1-2 were used to fabricate 1260mAh lithium-ion batteries in soft-pack form. Each lithium-ion battery includes a positive electrode, a negative electrode, a separator, an electrolyte, and battery auxiliary materials. The positive electrode active material is a ternary lithium-ion cathode material (LiNi). 0.6 Co 0.2 Mn 0.2 O2, the negative electrode active material is high-capacity graphite. The preparation process is as follows: the positive electrode sheet, separator and negative electrode sheet are wound together into a core, sealed with aluminum-plastic film and then baked to ensure that the electrode moisture meets the requirements. After baking, the cell is injected with electrolyte, and after standing, formation, capacity testing and aging processes, the finished lithium-ion battery soft pack cell is obtained.
[0047] The electrolytes from Examples 14-17 and Comparative Examples 3-4 were used to prepare 1000mAh soft-pack sodium-ion batteries. Each sodium-ion battery includes a positive electrode, a negative electrode, a separator, an electrolyte, and battery auxiliary materials. The positive electrode active material is a ternary positive electrode (NaNi). 0.33 Fe0.33 Mn 0.33 O2, with hard carbon as the negative electrode active material. The preparation process is as follows: the positive electrode, separator, and negative electrode are wound together into a core, sealed with aluminum-plastic film, and then baked to ensure that the electrode moisture content meets the requirements. After baking, the cell is injected with electrolyte, and after standing, formation, capacity testing, and aging processes, the finished sodium ion soft-pack cell is obtained.
[0048] The performance of the lithium-ion and sodium-ion batteries prepared above was tested, mainly including:
[0049] (1) Initial impedance test:
[0050] During the battery capacity grading stage: At room temperature (25℃), charge the battery with a constant current of 0.2C until the charging cutoff voltage, and then charge it with a constant voltage until the current drops to 0.05C; then discharge the battery with a constant current of 0.2C until the discharge cutoff voltage, and record the discharge capacity C1, which is the initial capacity of the battery.
[0051] Then charge at a constant current of 0.2C until the charging cutoff voltage, and charge at a constant voltage until the current drops to 0.05C; then discharge at a constant current of 0.2C until the capacity reaches 0.5*C1, which is 50% SOC state of charge, let stand for 2 hours, and record the voltage U1.
[0052] Finally, discharge the battery at a constant current of 4C for 30 seconds, record the voltage U2, and calculate the initial impedance of the battery:
[0053] Initial impedance = (U1 - U2) / 4 * 1000
[0054] (2) Low-temperature discharge performance test
[0055] The battery was discharged to 80% of its lower limit voltage at a discharge current of 1C in an oven at -20±1℃. This was taken as the low-temperature discharge capacity, and the percentage of this capacity to the 1C discharge capacity at 25℃ was calculated and recorded as the low-temperature discharge capacity retention rate.
[0056] (3) High-temperature storage performance test
[0057] At room temperature (25℃), the battery was charged at a constant current of 1C to the charging cutoff voltage (4.4V), and then charged at a constant voltage until the current dropped to 0.05C. It was then placed in a 60℃ constant temperature oven for 60 days. After storage, the battery was cooled to room temperature, and the initial volume V1 and the volume V2 after storage were recorded. The battery was then discharged at a constant current of 1C to the discharge cutoff voltage, and the initial discharge capacity C1 and the discharge capacity C2 after storage were recorded. The high-temperature storage volume expansion rate and capacity retention rate were calculated using the following formula:
[0058] High-temperature storage volume expansion rate = (V2 / V1-1)*100%
[0059] High-temperature storage capacity retention rate = C2 / C1 * 100%
[0060] (4) High-temperature cycling performance test
[0061] The battery was cycled in an oven at 45±1℃ with a charge / discharge current of 1C / 1C. The discharge capacity was calculated per cycle. The cycle was stopped after 500 cycles, and the capacity retention rate after the cycle was calculated.
[0062] The specific test results are shown in Table 2 below:
[0063] Table 2 Electrochemical performance test results
[0064]
[0065]
[0066] A comparison of Comparative Example 1 and Example 1 shows that using the diester compound alone can reduce battery impedance, improve low-temperature discharge performance, enhance high-temperature storage performance, and improve high-temperature cycling. A comparison of Comparative Example 2 and Example 15 shows that the diester compound also exhibits the same effects in sodium-ion batteries.
[0067] Comparative examples 2-5 show that as the content of diester compound I-1 in the electrolyte of the secondary battery gradually increases, more stable SEI films rich in organic phase can be formed, further improving the initial impedance, low-temperature discharge performance, high-temperature cycle performance and high-temperature storage performance of the secondary battery.
[0068] Comparing Examples 1 and 4 shows that further introducing boron-containing oxalate into the electrolyte can further reduce battery impedance and significantly improve low-temperature discharge, high-temperature storage, and high-temperature cycling performance, thus improving the overall performance of the battery. Comparing Examples 15 and 16 shows that the combined use of these two methods also exhibits a consistent improvement effect in sodium-ion batteries.
[0069] Comparative examples 4 and 6-9 show that compounds I-1, I-3, I-4, I-5, and I-8 all possess the functions of the representative additives and can be used interchangeably. Comparative examples 16-19 show that in sodium-ion batteries, compounds I-1, I-3, I-4, and I-5 also exhibit the functions of the representative additives and can be used interchangeably.
[0070] Comparing Examples 11 and 12-14 shows that the combined use of adding diester compounds, boron oxalate, and conventional additives such as VC, PS, and FEC can further improve the high and low temperature performance and storage performance of the battery. Meanwhile, comparing Example 16 shows that adding conventional additives to a sodium-ion battery can achieve the same effect.
Claims
1. An additive for secondary batteries, characterized in that: The additive comprises at least one diester compound represented by structural formula (I): In formula (I), R1 is a halogen, a substituted or unsubstituted C1-C6 alkyl, a substituted or unsubstituted C3-C9 cycloalkyl, or a substituted or unsubstituted C6-C18 aryl; R2 is a substituted or unsubstituted C1-C6 alkylene, a substituted or unsubstituted C2-C6 alkenyl, a substituted or unsubstituted C2-C6 alkyne, or a substituted or unsubstituted C6-C18 aryl; R3 is a halogen, a substituted or unsubstituted C1-C6 alkyl, a substituted or unsubstituted C2-C6 alkenyl, a substituted or unsubstituted C2-C6 alkyne, a substituted or unsubstituted C3-C7 cycloalkyl, a substituted or unsubstituted C3-C7 cycloalkenyl, or a substituted or unsubstituted C6-C18 aryl; X is -OC(=O)O-, -OS(=O)2O-, -OS(=O)O-, -S(=O)O-, or -OS(=O)-.
2. The additive for secondary batteries according to claim 1, characterized in that: R1 is a halogen, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C3-C7 cycloalkyl group, or a substituted or unsubstituted C6-C12 aryl group; R2 is a substituted or unsubstituted C1-C3 alkylene group, a substituted or unsubstituted C2-C4 alkenyl group, a substituted or unsubstituted C2-C4 alkyne group, or a substituted or unsubstituted C6-C12 aryl group; R3 is a halogen, a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C2-C4 alkenyl group, a substituted or unsubstituted C2-C4 alkyne group, or a substituted or unsubstituted C6-C12 aryl group.
3. The additive for secondary batteries according to claim 2, characterized in that: The diester compound represented by structural formula (I) is preferably at least one of the compounds represented by the following structures.
4. A non-aqueous electrolyte for secondary batteries, characterized in that: The non-aqueous electrolyte for the secondary battery contains a diester compound of structural formula (I) as described in any one of claims 1-3, in an amount of 0.001 to 3.0 wt% of the total mass of the electrolyte.
5. The non-aqueous electrolyte for secondary batteries according to claim 4, characterized in that: The preferred amount of the diester compound as a percentage of the total mass of the electrolyte is 0.01–2.0 wt%.
6. The non-aqueous electrolyte for secondary batteries according to claim 4, characterized in that: It also contains boron oxalate, in an amount of 0.01 to 10.0 wt% of the total electrolyte mass.
7. The non-aqueous electrolyte for secondary batteries according to claim 6, characterized in that: The boron oxalate is preferably at least one of LiDFOB, LiBOB, NaDFOB, or NaBOB, and its amount accounts for 0.1 to 5.0 wt% of the total mass of the electrolyte.
8. The non-aqueous electrolyte for secondary batteries according to claim 4, characterized in that: It contains a non-aqueous solvent, wherein the non-aqueous solvent is selected from at least one of C3-C6 carbonate or fluorocarbonate compounds, C3-C8 carboxylic acid esters or fluorocarboxylic acid ester compounds, sulfone compounds or ether compounds; Preferably, the C3-C6 carbonate or fluorocarbonate compound is selected from at least one of ethylene carbonate, propylene carbonate, butene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, or ethyl propyl carbonate; the C3-C8 carboxylic acid ester or fluorocarboxylic acid ester compound is selected from at least one of γ-butyrolactone, methyl acetate, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, ethyl butyrate, propyl acetate, or propyl propionate; the sulfone compound is selected from at least one of sulfolane, dimethyl sulfoxide, dimethyl sulfone, or diethyl sulfone; and the ether compound is selected from at least one of triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol dimethyl ether, or dioxolane.
9. The non-aqueous electrolyte for secondary batteries according to claim 4, characterized in that: It contains an electrolyte salt selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluorooxalate phosphate, lithium tri(oxalate) phosphate, lithium difluorobis(oxalate) phosphate, sodium hexafluorophosphate, sodium tetrafluoroborate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, and sodium difluorophosphate.
10. The non-aqueous electrolyte for secondary batteries according to any one of claims 4-9, characterized in that: The electrolyte contains a basic additive selected from at least one of vinylene carbonate, fluoroethylene carbonate, vinyl sulfate, vinyl sulfite, 4,4'-diethylene sulfate, 1,4-dioxane disulfate, tris(trimethylsilyl)phosphate, tris(trimethylsilyl)borate, 1,3-propanesulfonyl lactone, 1,3-propenesulfonyl lactone, lithium difluorophosphate, adiponitrile, cyclohexylbenzene, lithium difluorosulfonylimide, lithium difluorophosphate, lithium difluorodioxolane phosphate, sodium difluorosulfonylimide, sodium difluorophosphate, and sodium difluorodioxolane phosphate, such that any one basic additive accounts for 0.1 to 5.0 wt% of the total mass of the electrolyte.
11. A secondary battery, comprising a positive electrode, a negative electrode, and a separator, characterized in that: The secondary battery is filled with the non-aqueous electrolyte for secondary batteries as described in any one of claims 1-10.
12. The secondary battery according to claim 11, characterized in that: The positive electrode is selected from at least one of lithium cobalt oxide, lithium iron phosphate, lithium nickel manganese oxide, ternary materials of nickel cobalt manganese lithium, sodium-containing layered oxides, Prussian blue / white, and polyanions (sodium iron phosphate, sodium vanadium phosphate, etc.). The negative electrode is selected from graphite, silicon-carbon composite materials, lithium titanate, lithium metal, hard carbon, anthracite soft carbon, hard-soft composite carbon, etc.