Non-aqueous electrolyte, preparation method thereof and lithium ion battery
By adding a phosphorus-containing bicyclic compound to a non-aqueous electrolyte, a stable SEI film is formed and a conductive bridge is created inside the battery, solving the problem of SEI film instability in the prior art and improving the high-temperature cycling and storage performance of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- EVE POWER CO LTD
- Filing Date
- 2023-12-25
- Publication Date
- 2026-06-30
AI Technical Summary
The SEI film formed by existing electrolyte additives is not stable enough, which leads to severe lithium-ion consumption and rapid performance degradation of the battery during high-temperature cycling and storage.
Adding a first compound with a specific structure to a non-aqueous electrolyte, including an additive with a phosphorus-containing bicyclic structure, forms a dense and stable SEI film, and reduces the battery voltage by forming a conductive bridge through free radical ions during charge and discharge.
It improves the high-temperature cycling and storage performance of the battery, reduces the consumption of film-forming additives and side reactions, and enhances the battery's capacity retention and electrochemical performance.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrolyte materials technology, specifically relating to a non-aqueous electrolyte, its preparation method, and a lithium-ion battery. Background Technology
[0002] Rechargeable lithium-ion batteries, with their advantages of high energy density and long lifespan, have become an important component of energy storage devices, meeting the uninterrupted energy needs of everything from portable electronics to electric vehicles. However, without sacrificing energy density, the electrical performance of batteries during long-term cycling and high-temperature storage still faces significant challenges, mainly due to two factors: First, during long-term cycling, the solid electrolyte interphase (SEI) membrane undergoes continuous dynamic rupture and recombination, leading to continuous electrolyte consumption; second, during high-temperature storage, side reactions in the electrolyte intensify, resulting in a significant loss of active lithium ions.
[0003] To further improve the electrochemical performance of batteries, film-forming additives such as fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are frequently used in electrolytes. During the first cycle, the additives and electrolyte salts decompose to form an SEI film, which possesses electronic insulation and ionic conductivity. This effectively prevents solvent molecules from embedding into the electrode material and causing structural damage. For example, CN113690490A discloses a phosphite-based electrolyte additive with a methylene unsaturated phosphate structure. The methylene group provides electrons, increasing the electron cloud density of phosphorus atoms and exhibiting weak alkalinity. When applied to sulfate-based electrolytes, it effectively suppresses further increases in electrolyte acid value and color, thereby improving battery storage performance. CN111477958A discloses a sulfonyl phosphine oxide electrolyte additive. The sulfonyl group and P=O bond chemical structure facilitate the simultaneous formation of passivation films on both the negative and positive electrode surfaces, synergistically improving the electrochemical performance of lithium-ion batteries at high and low temperatures. CN114106047A discloses a phosphonoisocyanate-based electrolyte additive that utilizes the excellent film-forming properties of sulfonyl and isocyanate structural groups to promote the formation of a flexible SEI film on the negative electrode. This not only effectively suppresses the decrease in battery capacity during high-temperature cycling and high-temperature storage, but also suppresses the phenomenon of electrolyte decomposition and gas generation.
[0004] However, the electrolyte additives disclosed in the above-mentioned technical solutions all have a chain structure, and the resulting SEI film is still not stable enough. During high-temperature cycling and later storage, the SEI film structure will still be damaged, and a large amount of electrolyte and active lithium ions will still be consumed, resulting in a rapid decline in the battery's cycle performance and capacity retention.
[0005] Therefore, there is an urgent need in this field to develop an electrolyte system to solve the above problems. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the present invention aims to provide a non-aqueous electrolyte, its preparation method, and a lithium-ion battery. The non-aqueous electrolyte provided by the present invention can not only effectively reduce the internal impedance of the battery but also improve the battery's high-temperature cycling and storage performance, thereby enhancing the battery's capacity retention rate.
[0007] To achieve this objective, the present invention employs the following technical solution:
[0008] In a first aspect, the present invention provides a non-aqueous electrolyte, the non-aqueous electrolyte comprising an electrolyte salt, an additive, and a non-aqueous solvent, wherein the additive comprises a first compound having the structure shown in Formula 1:
[0009]
[0010] Wherein, R1 and R2 are each independently selected from any one of hydrogen atom, substituted or unsubstituted amino, alkyl, olefinic, substituted or unsubstituted silyl, substituted or unsubstituted siloxy, substituted or unsubstituted phenyl, and substituted or unsubstituted biphenyl.
[0011] The substituted groups include at least one of alkyl, silyl, and olefinic groups.
[0012] This invention involves adding a first compound with a specific structure to a non-aqueous electrolyte. During battery formation and charge / discharge, the phosphorus-containing bicyclic structure contained therein undergoes oxidative polymerization on the negative electrode surface. Due to the stable electron cloud distribution of the benzene ring and the stable spatial structure formed by the bicyclic structure, a dense and stable SEI film can be formed on the negative electrode surface. This SEI film exhibits excellent elasticity, capable of accommodating the significant volume changes of the carbon material during charge / discharge without rupture. Simultaneously, it effectively isolates the negative electrode from direct contact with the electrolyte, reducing the consumption of film-forming additives and the occurrence of side reactions.
[0013] In addition, the aforementioned first compound additive also has the function of preventing overcharging. When the battery charging voltage rises sharply, the polymer monomer molecules are oxidized into free radical ions in the solution, and these free radical ions couple into polymers in the solution. As the reaction proceeds, the polymer deposited on the cathode surface gradually increases, eventually penetrating the separator and forming a conductive bridge between the positive and negative electrodes, causing a micro-short circuit inside the battery, thereby reducing the battery voltage.
[0014] Preferably, the additive comprises a first compound having the structure shown in Formula 1:
[0015]
[0016] R1 and R2 are each independently selected from substituted or unsubstituted amino groups and substituted or unsubstituted silane groups.
[0017] The substituted groups include silyl groups.
[0018] Preferably, the first compound having the structure shown in Formula 1 comprises any one or a combination of at least two of the following structures:
[0019]
[0020] Preferably, based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of the first compound having the structure shown in Formula 1 is 0.1-1.0%, preferably 0.3-0.8%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc.
[0021] In this invention, by controlling the mass percentage content of the first compound having the structure shown in Formula 1, an SEI film of suitable thickness is formed on the negative electrode. If the content is too low, the SEI film formed by the first compound will be too thin and easily damaged, and will not be able to support long-term high-temperature cycling and storage performance; conversely, an excessively thick SEI film will be formed, consuming too many active lithium ions and increasing internal resistance, thereby reducing the battery's initial efficiency and capacity utilization.
[0022] Preferably, the additive also includes other additives.
[0023] Preferably, the other additives include vinylene sulfate and / or vinylene carbonate.
[0024] Preferably, based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of vinylene sulfate or vinylene carbonate is independently 0.5-3%, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.2%, 2.5%, 2.8%, 3%, etc.
[0025] Preferably, the electrolyte salt includes a lithium salt.
[0026] Preferably, the lithium salt includes any one or a combination of at least two of LiPF6, LiClO4, LiBF4, LiPO2F2, LiBOB, LiODFB, and LiFSI.
[0027] Preferably, the lithium salt content is 12-14% by mass, based on the total mass of the non-aqueous electrolyte as 100%, for example, it can be 12%, 12.2%, 12.5%, 12.8%, 13%, 13.2%, 13.5%, 13.8%, 14%, etc.
[0028] Preferably, the lithium salt comprises LiPF6 and / or LiPO2F2.
[0029] Preferably, the mass percentage of LiPF6 is 13-14% based on the total mass of the non-aqueous electrolyte as 100%, for example, it can be 13%, 13.2%, 13.5%, 13.8%, 14%, etc.
[0030] Preferably, based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of LiPO2F2 is 0.5-2%, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, etc.
[0031] In this invention, the selection of the above-mentioned lithium salt types and the control of their corresponding contents have the advantages of improving high-temperature cycling and storage.
[0032] Preferably, the non-aqueous solvent includes any two or at least three of the following: ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene sulfite, ethyl acetate, diethyl sulfite, and 1,3-propanesulfonate lactone; more preferably, it is a combination of any two or at least three of the following: ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.
[0033] Preferably, the non-aqueous solvent comprises a combination of at least three of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, and dimethyl carbonate.
[0034] Preferably, based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of ethylene carbonate is 15-45%, for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 30%, 35%, 40%, 45%, etc.
[0035] Preferably, based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of propylene carbonate is 0-20%, for example, it can be 0%, 0.2%, 0.5%, 0.8%, 1%, 2%, 3%, 4%, 5%, 8%, 10%, 15%, 16%, 17%, 18%, 19%, 20%, etc.
[0036] Preferably, based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of methyl ethyl carbonate is 3-45%, for example, it can be 3%, 4%, 5%, 8%, 10%, 15%, 16%, 17%, 18%, 19%, 20%, 25%, 30%, 35%, 40%, 41%, 42%, 43%, 44%, 45%, etc.
[0037] Preferably, based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of dimethyl carbonate is 15-21%, for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, etc.
[0038] In a second aspect, the present invention provides a method for preparing the non-aqueous electrolyte according to the first aspect, the method comprising the following steps:
[0039] The electrolyte salt, additives, and non-aqueous solvent are mixed to obtain the non-aqueous electrolyte, wherein the additives include a first compound having the structure shown in Formula 1:
[0040]
[0041] Wherein, R1 and R2 are each independently selected from any one of hydrogen atom, substituted or unsubstituted amino, alkyl, olefinic, substituted or unsubstituted silyl, substituted or unsubstituted siloxy, substituted or unsubstituted phenyl, and substituted or unsubstituted biphenyl.
[0042] The substituted groups include at least one of alkyl, silyl, and olefinic groups.
[0043] Thirdly, the present invention provides a lithium-ion battery, the lithium-ion battery comprising a casing and a cell and an electrolyte contained within the casing, the electrolyte comprising the non-aqueous electrolyte according to the first aspect.
[0044] Preferably, the battery cell includes a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode.
[0045] Preferably, the material of the positive electrode sheet includes a positive electrode active material, a positive electrode binder, and a conductive agent.
[0046] Preferably, the material of the negative electrode sheet includes a negative electrode active material, a negative electrode binder, and a conductive agent.
[0047] In this invention, the above-mentioned positive electrode binder, negative electrode binder and conductive agent are all positive electrode binders, negative electrode binders and conductive agents commonly used by those skilled in the art, and this invention does not impose any restrictions on them.
[0048] In this invention, the conductive agent of the positive electrode and the conductive agent of the negative electrode can be the same or different.
[0049] Compared with the prior art, the present invention has the following beneficial effects:
[0050] This invention provides a non-aqueous electrolyte. By adding a first compound with a specific structure to the non-aqueous electrolyte, the phosphorus-containing bicyclic structure contained therein can oxidize and polymerize on the negative electrode surface during battery formation and charge / discharge processes. Due to the stable electron cloud distribution of the benzene ring and the stable spatial structure formed by the bicyclic structure, a dense and stable SEI film can be formed on the negative electrode surface. The aforementioned SEI film has excellent elasticity, can adapt to the huge volume changes of carbon materials during charge / discharge without breaking, and effectively isolates the negative electrode from direct contact with the electrolyte, reducing the consumption of film-forming additives and the occurrence of side reactions.
[0051] In addition, the aforementioned first compound additive also has the function of preventing overcharging. When the battery charging voltage rises sharply, the polymer monomer molecules are oxidized into free radical ions in the solution, and these free radical ions couple into polymers in the solution. As the reaction proceeds, the polymer deposited on the cathode surface gradually increases, eventually penetrating the separator and forming a conductive bridge between the positive and negative electrodes, causing a micro-short circuit inside the battery, thereby reducing the battery voltage. Detailed Implementation
[0052] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.
[0053] Example 1
[0054] This embodiment provides a non-aqueous electrolyte. Based on the total mass of the non-aqueous electrolyte (100%), the non-aqueous electrolyte comprises 13% lithium hexafluorophosphate, 0.5% of the first compound additive of formula 1-1, 3% vinylene carbonate, and 0.5% lithium difluorophosphate by mass percentage, with the balance being a non-aqueous solvent. The non-aqueous solvent is prepared by mixing dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, and propylene carbonate in a mass ratio of 5:1:10:4.
[0055] The method for preparing the non-aqueous electrolyte is as follows:
[0056] The electrolyte was prepared in a glove box, where the actual oxygen content and moisture content were <0.1 ppm and <0.1 ppm, respectively. The components were mixed and stirred under vacuum to prepare a non-aqueous electrolyte.
[0057] The preparation method of lithium-ion batteries is as follows:
[0058] Positive electrode preparation: First, a gel solution with a solid content of 1.327% was prepared. Lithium iron phosphate, conductive agent Super-P, and N-methylpyrrolidone (NMP) were added, and the mixture was rotated at 25 r / min, dispersed at 500 r / min, and stirred for 10 min. Then, it was rotated at 25 r / min, dispersed at 1000 r / min, and stirred at 45℃ for 90 min. Next, a conductive agent carbon nanotube slurry was added, and the mixture was rotated at 25 r / min, dispersed at 1000 r / min, and stirred at 45℃ for 60 min under a vacuum of 0.080 kPa. Finally, the gel solution was added, and the mixture was rotated at 25 r / min and dispersed at 2500 r / min. The mixture was stirred at 45℃ for 90 minutes under a vacuum of 0.080 kPa. NMP was then added to adjust the slurry viscosity. Finally, the mixture was slowly stirred at 15 r / min and dispersed at 500 r / min under a vacuum of 0.080 kPa for 0.5 hours before cooling down to ensure that the positive electrode discharge viscosity was 20000 mPa·s and the fineness was ≤15 μm. The deposited material on the stirring cylinder wall and stirring rod was scraped off in time at each step. The positive electrode sheet was obtained by sieving, coating, cold pressing and slitting. The mass ratio of lithium iron phosphate, conductive agent Super-P, carbon nanotubes and binder polyvinylidene fluoride was 95.0:2.0:0.5:2.5.
[0059] Negative electrode preparation: First, prepare a slurry with a solid content of 8%, add graphite and conductive agent Super-P for dry mixing, rotate at 20 r / min, disperse at 1000 r / min, and stir for 1 h; then add 50% negative electrode slurry, rotate at 20 r / min, disperse at 1000 r / min, and stir for 1.5 h; then add another 50% negative electrode slurry, rotate at 25 r / min, disperse at 2000 r / min, vacuum degree 0.085 kPa, and stir for 1 h; then add deionized water to adjust the slurry viscosity; finally add the aqueous dispersant styrene-butadiene latex, rotate at 25 r / min, disperse at 800 r / min, vacuum degree 0.085 kPa, and stir for 1 h to finish. The negative electrode material is guaranteed to have a viscosity of 4000 mPa·s and a fineness of ≤20 μm. The material deposited on the mixing tank wall and mixing rod is scraped off in time at each step. The negative electrode sheet is obtained by sieving, coating, cold pressing and slitting. The mass ratio of the negative electrode active material graphite, conductive agent Super-P, thickener sodium carboxymethyl cellulose and binder styrene-butadiene latex is 95.5:1.5:1.2:1.8.
[0060] Lithium-ion battery preparation: The prepared positive electrode sheet, negative electrode sheet and separator are stacked to obtain a bare cell. After the cell is put into an aluminum-plastic film packaging shell, the above-mentioned electrolyte is injected. Then, the processes of sealing, standing, hot and cold pressing, formation and capacity testing are carried out to obtain a lithium-ion battery.
[0061] Example 2
[0062] The difference between this embodiment and Embodiment 1 is that the first compound of Formula 1-1 is replaced with an equal amount of the first compound of Formula 1-2, while all other aspects are the same as in Embodiment 1.
[0063] Example 3
[0064] The difference between this embodiment and Embodiment 1 is that the first compound of Formula 1-1 is replaced with an equal amount of the first compound of Formula 1-3, while all other aspects are the same as in Embodiment 1.
[0065] Example 4
[0066] The difference between this embodiment and Example 1 is that the first compound of Formula 1-1 is replaced with an equal amount of the first compound of Formula 1-4, while all other aspects are the same as in Example 1.
[0067] Example 5
[0068] The difference between this embodiment and Embodiment 1 is that the first compound of Formula 1-1 is replaced with an equal amount of the first compound of Formula 1-5, while all other aspects are the same as in Embodiment 1.
[0069] Example 6
[0070] The difference between this embodiment and Example 1 is that lithium difluorophosphate is not added, and the content of non-aqueous solvent is adaptively adjusted so that the total mass percentage of the system is 100%. Everything else is the same as in Example 1.
[0071] Example 7
[0072] The difference between this embodiment and Example 1 is that, based on the total mass of the non-aqueous electrolyte as 100%, vinylene carbonate is not added, and the mass percentage of the first compound additive of Formula 1-1 is adjusted to 3.5%. Everything else is the same as in Example 1.
[0073] Example 8
[0074] The difference between this embodiment and Embodiment 1 is that lithium difluorophosphate is replaced with an equal amount of LiFSI, while everything else is the same as in Embodiment 1.
[0075] Example 9
[0076] The difference between this embodiment and Example 1 is that the non-aqueous solvent is prepared by mixing ethylene carbonate and propylene carbonate in a mass ratio of 3:7, while all other aspects are the same as in Example 1.
[0077] Comparative Example 1
[0078] The difference between this comparative example and Example 1 is that the first compound of formula 1-1 is not added, and the content of the non-aqueous solvent is adaptively adjusted so that the mass percentage of the total system is 100%. Everything else is the same as in Example 1.
[0079] Comparative Example 2
[0080] The difference between this comparative example and Example 1 is that, based on the total mass of the non-aqueous electrolyte as 100%, the first compound of formula 1-1 is not added, the mass percentage of vinylene carbonate is 3.5%, and everything else is the same as in Example 1.
[0081] Comparative Example 3
[0082] The difference between this comparative example and Example 1 is that, with the total mass of the non-aqueous electrolyte being 100%, the first compound of Formula 1-1 and lithium difluorophosphate are not added, and the content of the non-aqueous solvent is adaptively adjusted so that the mass percentage of the total system is 100%. Everything else is the same as in Example 1.
[0083] Comparative Example 4
[0084] This comparative example provides an additive with the structure shown in CN109473719A.
[0085] Test conditions
[0086] The lithium-ion batteries provided in Examples 1 to 9 and Comparative Examples 1 to 4 were tested using the following methods:
[0087] (1) High-temperature cycle performance: At room temperature (25℃), the volume of fresh lithium-ion batteries was tested using the water displacement method and recorded as V1. At high temperature (45℃), the above lithium-ion batteries were charged to 3.65V under 1C constant current and constant voltage conditions, and then discharged to 2.5V under 1C constant current conditions. This charge-discharge cycle was repeated for more than 1000 cycles, and the capacity retention rate after the 1000th cycle was recorded.
[0088] (Discharge capacity after 1000 cycles / Discharge capacity after the first cycle) × 100%. After 1000 cycles, the volume is measured again using the water displacement method and recorded as V2.
[0089] Volume expansion rate = (V2-V1) / V1×100%;
[0090] (2) High-temperature storage performance: Under normal temperature (25℃) conditions, the volume of fresh lithium-ion batteries was measured using the water displacement method and recorded as V1. The lithium-ion batteries were subjected to 5 cycles of 1C / 1C charging and discharging, and the average discharge capacity of the last 3 cycles was recorded as Q1. Then, the batteries were charged to 3.65V under 1C constant current and constant voltage conditions. The fully charged lithium-ion batteries were then stored in a 60℃ high-temperature chamber for 90 days. After removal, they were discharged at 1C under normal temperature conditions (discharge capacity recorded as Q2), and the volume was measured again using the water displacement method and recorded as V2. The capacity retention rate and volume expansion rate of the lithium-ion batteries were calculated using the following formulas:
[0091] Capacity retention rate = Q2 / Q1 × 100%;
[0092] Volume expansion rate = (V2-V1) / V1×100%;
[0093] (3) Internal resistance: Use a multimeter to test and record the internal resistance of a fresh lithium-ion battery.
[0094] The test results are shown in Table 1:
[0095] Table 1
[0096]
[0097] As shown in Table 1, Examples 1, 2, 3, 4, and 5 exhibit similar high-temperature cycling and storage performance, and their internal resistance is relatively low. Among them, the battery provided in Example 1 demonstrates the best overall performance, showing a significant improvement over Comparative Example 1. This indicates that the introduction of the phosphorus-containing bicyclic structure provided by this invention enhances battery performance. The bicyclic structure possesses a stable electron cloud, and the P=O bonds facilitate film formation at the negative electrode. The synergistic effect of these two elements enables the formation of a stable SEI film structure at the lithium-ion battery negative electrode, mitigating the side reactions between the electrolyte and the negative electrode, thereby improving the battery's high-temperature cycling and storage stability.
[0098] Examples 1 and 7 and Comparative Example 2 show that Example 7 indicates that when only the first compound additive of Formula 1-1 is used, the internal resistance of the battery increases, and the gas production also increases, resulting in poor high-temperature cycle performance and high-temperature storage performance. Comparative Example 2 shows that when the amount of the single vinylene carbonate film-forming additive is 3.5%, the performance of the lithium-ion battery is lower than that of the combination of the two. This phenomenon can be attributed to the excessive decomposition of the single vinylene carbonate film-forming additive on the negative electrode surface, forming a thicker SEI film, which leads to the faster consumption of the film-forming additive in the system. Therefore, it is indicated that further control of the content of the first compound with the structure shown in Formula 1 and the vinylene carbonate film-forming additive can result in lower internal resistance, less gas production, and good high-temperature cycle and high-temperature storage performance of the battery.
[0099] A comparison of Examples 1, 6, and 8 reveals that, since lithium salt LiPO2F2 can also form a film on the negative electrode surface, its combined use with the first compound of Formula 1-1 results in a battery that comprehensively improves high-temperature cycling and storage performance with minimal impedance increase. A comparison of Examples 1 and 9 shows that the addition of dimethyl carbonate and ethyl methyl carbonate, solvents with low viscosity, helps reduce the battery's internal resistance, thereby improving the overall performance of the lithium iron phosphate battery system.
[0100] A comparison of Example 1 and Comparative Example 4 shows that the prior art cathode film-forming additives are not suitable for lithium iron phosphate systems. However, the first compound with a specific structure proposed in this invention can more easily form a film on the anode in lithium iron phosphate systems through oxidation.
[0101] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.
Claims
1. A non-aqueous electrolyte, characterized in that, The non-aqueous electrolyte includes electrolyte salts, additives, non-aqueous solvents, and other additives, the additives including a first compound having the structure shown in Formula 1: Formula 1 Wherein, R1 and R2 are each independently selected from any one of hydrogen atom, substituted or unsubstituted amino, alkyl, olefinic, substituted or unsubstituted silyl, substituted or unsubstituted siloxy, substituted or unsubstituted phenyl, and substituted or unsubstituted biphenyl. The substituted groups include at least one of alkyl, silyl, and olefin groups; The other additives include vinylene sulfate and / or vinylene carbonate; The non-aqueous solvents include ethylene carbonate, propylene carbonate, ethyl methyl carbonate, and dimethyl carbonate; Based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of the first compound having the structure shown in Formula 1 is 0.1-1.0%, the mass percentage of vinylene sulfate or vinylene carbonate is independently 0.5-3%, the mass percentage of methyl ethyl carbonate is 3-45%, and the mass percentage of dimethyl carbonate is 15-21%.
2. The non-aqueous electrolyte according to claim 1, characterized in that, The additive includes a first compound having the structure shown in Formula 1: Formula 1 R1 and R2 are each independently selected from substituted or unsubstituted amino groups and substituted or unsubstituted silane groups. The substituted groups include silyl groups.
3. The non-aqueous electrolyte according to claim 1, characterized in that, The first compound having the structure shown in Formula 1 includes any one or a combination of at least two of the following structures: Equation 1-1 Equation 1-2 Equation 1-3 Equations 1-4 and 1-5.
4. The non-aqueous electrolyte according to claim 1, characterized in that, Based on the total mass of the non-aqueous electrolyte being 100%, the mass percentage of the first compound having the structure shown in Formula 1 is 0.3-0.8%.
5. The non-aqueous electrolyte according to claim 1, characterized in that, The electrolyte salt includes lithium salt.
6. The non-aqueous electrolyte according to claim 5, characterized in that, The lithium salt includes any one or a combination of at least two of LiPF6, LiClO4, LiBF4, LiPO2F2, LiBOB, LiODFB, and LiFSI.
7. The non-aqueous electrolyte according to claim 5, characterized in that, Based on the total mass of the non-aqueous electrolyte being 100%, the mass percentage of the lithium salt is 12-14%.
8. The non-aqueous electrolyte according to claim 5, characterized in that, The lithium salt includes LiPF6 and / or LiPO2F2.
9. The non-aqueous electrolyte according to claim 8, characterized in that, Based on the total mass of the non-aqueous electrolyte being 100%, the mass percentage of LiPF6 is 13-14%.
10. The non-aqueous electrolyte according to claim 8, characterized in that, Based on the total mass of the non-aqueous electrolyte being 100%, the mass percentage of LiPO2F2 is 0.5-2%.
11. The non-aqueous electrolyte according to claim 1, characterized in that, Based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of ethylene carbonate is 15-45%.
12. The non-aqueous electrolyte according to claim 1, characterized in that, Based on the total mass of the non-aqueous electrolyte as 100%, the mass percentage of propylene carbonate is 0.2-20%.
13. A method for preparing a non-aqueous electrolyte according to any one of claims 1-12, characterized in that, The method includes the following steps: The electrolyte salt, additives, non-aqueous solvent, and other additives are mixed to obtain the non-aqueous electrolyte, wherein the additives include a first compound having the structure shown in Formula 1: Formula 1 Wherein, R1 and R2 are each independently selected from any one of hydrogen atom, substituted or unsubstituted amino, alkyl, olefinic, substituted or unsubstituted silyl, substituted or unsubstituted siloxy, substituted or unsubstituted phenyl, and substituted or unsubstituted biphenyl. The substituted groups include at least one of alkyl, silyl, and olefinic groups.
14. A lithium-ion battery, characterized in that, The lithium-ion battery includes a casing and a cell and an electrolyte contained within the casing, wherein the electrolyte includes a non-aqueous electrolyte according to any one of claims 1-12.