An electrolyte and lithium-ion battery and its preparation method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-16
- Publication Date
- 2026-08-14
AI Technical Summary
[0004]本发明的目的在于提供一种电解液与锂离子电池及其制备方法，以解决或改善上述技术问题
本发明通过在一注电解液中加入成膜添加剂，可形成高稳定高质量的SEI膜，有效改善电解液与电极材料的兼容性，防止部分阻燃成分直接在石墨负极表面被还原分解，从而提高电池的充放电性能。在二注电解液中采用磷酸酯类化合物作为阻燃成分，既可保持良好的阻燃效果，又不会降低电导率，有效解决了现有技术中阻燃添加剂影响电池充放电性能的问题。本发明提供的电解液具有优异的电化学性能和阻燃效果，可以提高电芯的安全性和循环寿命，并且该上述一注电解液以及二注电解液均通过各成分混合即可，制备方法简单可行，成本适中，具有良好的工业化应用前景。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of battery materials technology, and more specifically, to an electrolyte and a lithium-ion battery and a method for preparing the same. Background Technology
[0002] With the increasing application of lithium-ion batteries in power and energy storage, their safety has become a prominent issue. Phosphate esters are often used as flame retardants to effectively improve safety; however, these substances exhibit high film-forming resistance on the negative electrode surface and cannot form a complete film. When used in large quantities, phosphate ester molecules co-intercalate with lithium ions between graphite layers, causing graphite expansion and peeling, severely damaging the lifespan of lithium batteries. If the content is too low, their excellent flame-retardant properties cannot be fully realized. Therefore, it is necessary to find an electrolyte that balances high flame retardancy with excellent electrochemical performance.
[0003] In view of this, the present invention is proposed. Summary of the Invention
[0004] The purpose of this invention is to provide an electrolyte and a lithium-ion battery and a method for preparing the same, so as to solve or improve the above-mentioned technical problems.
[0005] This invention can be implemented as follows: In a first aspect, the present invention provides an electrolyte, comprising a first electrolyte injection and a second electrolyte injection; One electrolyte solution comprises a first lithium salt, a first organic solvent, and a film-forming additive; The second electrolyte comprises a second lithium salt, a flame retardant component, and a second organic solvent; the flame retardant component comprises at least one of a phosphate ester compound and a phosphite ester compound.
[0006] In an optional embodiment, the electrolyte comprises 3 wt% to 5 wt% of film-forming additives, based on the total mass of the electrolyte in a single injection of 100%.
[0007] In an optional embodiment, the film-forming additive includes at least one of VC, FEC, DTD, MMDS and PS.
[0008] In an optional embodiment, the two electrolytes, based on a total mass of 100%, include 40wt% to 55wt% flame-retardant components.
[0009] In an optional embodiment, the flame retardant component includes phosphate ester compounds and phosphite compounds; wherein the phosphate ester compounds include at least one of trimethyl phosphate, triethyl phosphate and triphenyl phosphate; and the phosphite compounds include at least one of trimethyl phosphite, triethyl phosphite and tris(2,2,2-trifluoroethyl) phosphite.
[0010] In an optional embodiment, based on the total mass of one electrolyte injection being 100%, the electrolyte injection further includes 6wt% to 35wt% of a first lithium salt.
[0011] In an optional embodiment, the first lithium salt includes at least one of LiPF6, LiFSI, and LiTFSI.
[0012] In an optional embodiment, the electrolyte further comprises 60wt% to 91wt% of a first organic solvent, based on the total mass of the electrolyte being 100%.
[0013] In an optional embodiment, the first organic solvent includes at least one of a linear carbonate and a cyclic carbonate, wherein the linear carbonate includes at least one of DMC and EMC, and the cyclic carbonate includes EC.
[0014] In an optional embodiment, the second electrolyte further comprises 6 wt% to 35 wt% of a second lithium salt, based on the total mass of the two electrolytes being 100%.
[0015] In an optional embodiment, the second lithium salt includes at least one of LiPF6, LiFSI, and LiTFSI.
[0016] In an optional embodiment, the second electrolyte further comprises 10wt% to 54wt% of a second organic solvent, based on the total mass of the two electrolytes being 100%.
[0017] In an optional embodiment, the second organic solvent includes at least one of linear carbonates and cyclic carbonates, wherein the linear carbonates include at least one of DMC and EMC, and the cyclic carbonates include EC.
[0018] In an optional implementation, the mass ratio of the first electrolyte injection to the second electrolyte injection is 7:3 to 9:1.
[0019] Secondly, the present invention provides a lithium-ion battery comprising the electrolyte of any of the foregoing embodiments.
[0020] Thirdly, the present invention provides a method for preparing a lithium-ion battery as described in the foregoing embodiments, comprising the following steps: stacking a positive electrode, a separator and a negative electrode in sequence, followed by stacking, hot pressing, baking, injecting one electrolyte, high-temperature standing, formation, aging, injecting a second electrolyte, and capacity testing.
[0021] The beneficial effects of this invention include: This invention, by adding film-forming additives to the primary electrolyte, forms a highly stable and high-quality SEI film, effectively improving the compatibility between the electrolyte and electrode materials and preventing some flame-retardant components from being directly reduced and decomposed on the graphite anode surface, thereby improving the battery's charge-discharge performance. In the secondary electrolyte, phosphate ester compounds are used as flame-retardant components, maintaining good flame-retardant effects without reducing conductivity, effectively solving the problem of flame-retardant additives affecting battery charge-discharge performance in existing technologies. The electrolyte provided by this invention has excellent electrochemical performance and flame-retardant effects, improving cell safety and cycle life. Furthermore, both the primary and secondary electrolytes can be prepared simply by mixing the components, making the preparation method simple, feasible, and cost-effective, with promising prospects for industrial application. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0023] The electrolyte, lithium-ion battery, and their preparation method provided by the present invention will be described in detail below.
[0024] The present invention provides an electrolyte, comprising a primary electrolyte and a secondary electrolyte.
[0025] The first electrolyte comprises a first lithium salt, a first organic solvent, and a film-forming additive. The second electrolyte comprises a second lithium salt, a flame-retardant component, and a second organic solvent; the flame-retardant component comprises at least one of a phosphate ester compound and a phosphite ester compound.
[0026] In some optional embodiments, the mass ratio of the first electrolyte to the second electrolyte can be from 7:3 to 9:1, such as 7:3, 7.5:2.5, 8:2, 8.5:1.5, or 9:1, or other values within the range of 7:3 to 9:1. If the mass ratio of the first electrolyte to the second electrolyte is less than 7:3 (e.g., 6:4), it is not conducive to film formation in the first electrolyte; if the mass ratio of the first electrolyte to the second electrolyte is greater than 9:1 (e.g., 9.5:0.5), it is not conducive to flame retardancy.
[0027] In some alternative implementations, the electrolyte injection coefficient can be 3.5 g / Ah.
[0028] In some optional embodiments, a portion of the electrolyte comprises 6 wt% to 35 wt% of a first lithium salt. For example, the content of the first lithium salt in a portion of the electrolyte can be 6 wt%, 10 wt%, 20 wt%, 30 wt%, or 35 wt%, or other values within the range of 6 wt% to 35 wt%. The first lithium salt may exemplary include at least one of LiPF6 (lithium hexafluorophosphate), LiFSI (lithium difluorobis(sulfonyl)imide), and LiTFSI (lithium bis(trifluoromethanesulfonyl)imide).
[0029] One electrolyte solution comprises 60 wt% to 91 wt% of a first organic solvent. For example, the content of the first organic solvent in one electrolyte solution can be 60 wt%, 79 wt%, or 90 wt%, or other values within the range of 60 wt% to 91 wt%. The first organic solvent comprises at least one of linear carbonates and cyclic carbonates, wherein the linear carbonates may exemplary include at least one of DMC (dimethyl carbonate) and EMC (ethyl methyl carbonate), and the cyclic carbonates may exemplary include EC (ethylene carbonate).
[0030] One electrolyte may also include 3 wt% to 5 wt% of film-forming additives. For example, the content of film-forming additives in one electrolyte may be 3 wt%, 4 wt%, or 5 wt%, or other values within the range of 3 wt% to 5 wt%. If the content of film-forming additives in one electrolyte is too low, it is not conducive to the formation of a highly stable and high-quality SEI film; if the content of film-forming additives in one electrolyte is too high, it is not conducive to electrolyte wetting, and the film impedance will also be high. The above-mentioned film-forming additives may, by example, include at least one of VC (ethylene carbonate), FEC (fluoroethylene carbonate), DTD (ethylene sulfate), MMDS (methylene disulfonate), and PS (1,3-propanesulfonate lactone).
[0031] In some preferred embodiments, one electrolyte comprises 12.5 wt% LiPF6, 3.1 wt% LiFSI, 79.4 wt% a first organic solvent, 2.5 wt% VC, 1.4 wt% FEC, 0.8 wt% DTD, and 0.3 wt% MMDS. The first organic solvent is composed of EC, EMC, and DMC in a mass ratio of 3:1:6.
[0032] In some alternative embodiments, the secondary electrolyte does not include film-forming additives to avoid increasing side reactions, which could lead to increased film resistance and electrolyte system viscosity, affecting electrochemical performance and flame retardant effect.
[0033] In some optional embodiments, the secondary electrolyte comprises 6 wt% to 35 wt% of a second lithium salt. For example, the content of the second lithium salt in the secondary electrolyte can be 6 wt%, 10 wt%, 20 wt%, 30 wt%, or 35 wt%, or other values within the range of 6 wt% to 35 wt%. The aforementioned second lithium salt may, exemplarily, include at least one of LiPF6, LiFSI, and LiTFSI.
[0034] The secondary electrolyte contains 40wt% to 55wt% flame-retardant components. For example, the content of flame-retardant components in the secondary electrolyte can be 40wt%, 50wt%, or 55wt%, or other values within the range of 40wt% to 55wt%. If the content of flame-retardant components in the secondary electrolyte is too low, it will not be conducive to the flame-retardant effect; if the content of flame-retardant components in the secondary electrolyte is too high, it will not be conducive to electrolyte wetting. The aforementioned flame-retardant components include phosphate ester compounds and phosphite compounds; wherein, phosphate ester compounds may exemplary include at least one of trimethyl phosphate, triethyl phosphate, and triphenyl phosphate; phosphite compounds may exemplary include at least one of trimethyl phosphite, triethyl phosphite, and tris(2,2,2-trifluoroethyl) phosphite.
[0035] The secondary electrolyte comprises 10 wt% to 54 wt% of a second organic solvent. For example, the content of the second organic solvent in the secondary electrolyte can be 10 wt%, 42 wt%, or 54 wt%, or other values within the range of 10 wt% to 54 wt%. The aforementioned second organic solvent comprises at least one of linear carbonates and cyclic carbonates, wherein the linear carbonates may exemplary include at least one of DMC and EMC, and the cyclic carbonates may exemplary include EC.
[0036] In some preferred embodiments, the secondary electrolyte comprises 12.5 wt% LiPF6, 3.1 wt% LiFSI, 42.2 wt% flame retardant components, and 42.2 wt% DMC; wherein the flame retardant components are composed of triethyl phosphate, trimethyl phosphate, and triphenyl phosphate in a mass ratio of 8:1:1.
[0037] Building upon the above, the electrolyte provided by this invention possesses both excellent electrochemical and flame-retardant properties. One electrolyte layer contains suitable film-forming additives, which, after formation treatment, enable the first electrolyte layer to form a highly stable, high-quality SEI film on the negative electrode surface. This effectively improves the compatibility between the electrolyte and electrode materials, preventing some flame-retardant components from being directly reduced and decomposed on the graphite negative electrode surface, thereby improving the battery's charge-discharge performance. The second electrolyte layer uses phosphate ester compounds as flame-retardant components, maintaining good flame-retardant effects without reducing conductivity, effectively solving the problem of flame-retardant additives affecting battery charge-discharge performance in existing technologies. The electrolyte provided by this invention exhibits excellent electrochemical performance and flame-retardant effects, improving cell safety and cycle life. Furthermore, its preparation method is simple and feasible, achieved through component mixing, and is cost-effective, showing promising prospects for industrial application.
[0038] Accordingly, the present invention also provides a lithium-ion battery comprising the above-described electrolyte.
[0039] In addition, the present invention also provides a method for preparing the above-mentioned lithium-ion battery, comprising the following steps: stacking the positive electrode, separator and negative electrode in sequence, followed by stacking, hot pressing, baking, injecting one electrolyte, high-temperature standing, formation, aging, injecting a second electrolyte, and capacity testing.
[0040] In some alternative embodiments, lithium iron phosphate powder is mixed with a conductive agent (such as conductive carbon black), a binder (such as polyvinylidene fluoride, PVDF) and a solvent (such as N-methylpyrrolidone, NMP) in a certain proportion to obtain a positive electrode slurry. The slurry is coated on aluminum foil and then subjected to drying, rolling, slitting and die-cutting processes to obtain a positive electrode sheet.
[0041] Graphite is used as the main negative electrode material and is mixed with conductive agent, binder and dispersant respectively. The mixture is homogenized with deionized water to obtain negative electrode slurry. The negative electrode slurry is coated on carbon-coated copper foil and then dried, rolled, slit and die-cut to obtain negative electrode sheet.
[0042] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as an isolation between the positive and negative electrodes. Then, the soft-pack battery cell is obtained through the following processes: stacking, hot pressing, baking, first liquid injection, high-temperature standing, formation, aging, second liquid injection, capacity testing, and OCV.
[0043] The diaphragm can be a PP film, the capacity of the soft-pack battery cell can be 5Ah, the cell height can be 7.6cm, and the thickness can be 7.3mm.
[0044] This invention forms a film in the first injection, and the phosphate ester component introduced in the second injection no longer directly contacts the fresh negative electrode, thus effectively suppressing its decomposition reaction. This imparts flame retardancy to the electrolyte while protecting the stability of the interface. It solves the problems of high film-forming resistance and graphite peeling caused by incompatibility between flame retardant additives and graphite in the prior art, while also giving full play to its excellent flame retardant effect. Moreover, the manufacturing process is simple and low in cost.
[0045] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0046] Example 1 This embodiment provides an electrolyte, including a first electrolyte and a second electrolyte with a mass ratio of 9:1.
[0047] Based on the total mass of one electrolyte, one electrolyte comprises 15.6 wt% of the first lithium salt (12.5 wt% of LiPF6 and 3.1 wt% of LiFSI), 79.4 wt% of the first organic solvent (composed of EC, EMC and DMC in a mass ratio of 3:1:6), and 5 wt% of film-forming additives (2.5 wt% of VC, 1.4 wt% of FEC, 0.8 wt% of DTD and 0.3 wt% of MMDS).
[0048] Based on the total mass of the two electrolytes as 100%, the two electrolytes include 15.6 wt% of the second lithium salt (12.5 wt% of LiPF6 and 3.1 wt% of LiFSI), 42.2 wt% of the second organic solvent (all of which is DMC) and 42.2 wt% of the flame retardant component (composed of triethyl phosphate, trimethyl phosphate and triphenyl phosphate in a mass ratio of 8:1:1).
[0049] Example 2 The difference between this embodiment and Example 1 is that the content of film-forming additives is reduced, specifically as follows: one electrolyte contains 3.1 wt% film-forming additives, specifically 1.5 wt% VC, 1 wt% FEC, 0.5 wt% DTD, and 0.1 wt% MMDS. The reduced amount is made up by the first organic solvent.
[0050] Example 3 The difference between this embodiment and Embodiment 1 is that the flame retardant composition in the second electrolyte has been adjusted. Specifically, the flame retardant composition in the second electrolyte consists of triethyl phosphate, trimethyl phosphate, and triphenyl phosphate in a mass ratio of 4:5:1.
[0051] Example 4 This embodiment provides an electrolyte, including a first electrolyte and a second electrolyte with a mass ratio of 7:3.
[0052] Based on the total mass of one electrolyte, one electrolyte comprises 15.6 wt% of the first lithium salt (12.5 wt% of LiPF6 and 3.1 wt% of LiFSI), 79.4 wt% of the first organic solvent (composed of EC, EMC and DMC in a mass ratio of 3:1:10), and 5 wt% of film-forming additives (2.5 wt% of VC, 1 wt% of FEC, 0.5 wt% of DTD, 0.5 wt% of MMDS and 0.5 wt% of PS).
[0053] Based on the total mass of the two electrolytes as 100%, the two electrolytes include 15.6 wt% of the second lithium salt (12.5 wt% of LiPF6 and 3.1 wt% of LiFSI), 42.2 wt% of the second organic solvent (all of which is DMC) and 42.2 wt% of the flame retardant component (composed of triethyl phosphate, trimethyl phosphate and triphenyl phosphate in a mass ratio of 6:1:1).
[0054] Example 5 This example provides an electrolyte, including a first electrolyte and a second electrolyte with a mass ratio of 8:2.
[0055] Based on the total mass of one electrolyte, one electrolyte comprises 15.6 wt% of the first lithium salt (12.5 wt% of LiPF6 and 3.1 wt% of LiFSI), 79.4 wt% of the first organic solvent (composed of EC, EMC and DMC in a mass ratio of 2:3:5), and 5 wt% of film-forming additives (1 wt% of VC, 1 wt% of FEC, 1 wt% of DTD, 1 wt% of MMDS and 1 wt% of PS).
[0056] Based on the total mass of the two electrolytes as 100%, the two electrolytes include 15.6 wt% of the second lithium salt (12.5 wt% of LiPF6 and 3.1 wt% of LiFSI), 42.2 wt% of the second organic solvent (all EC), and 42.2 wt% of the flame retardant component (composed of triethyl phosphate, trimethyl phosphate, and triphenyl phosphate in a mass ratio of 12:3:1).
[0057] Comparative Example 1 The difference between this comparative example and Example 1 is that the flame-retardant component from the two electrolyte solutions is added to one electrolyte solution. Everything else is the same as in Example 1.
[0058] Comparative Example 2 The difference between this comparative example and Example 1 is that a film-forming additive was added to the second electrolyte. This resulted in the second electrolyte comprising, by weight (100%), 15.6 wt% of a second lithium salt (12.5 wt% LiPF6 and 3.1 wt% LiFSI), 39.7 wt% of a second organic solvent (all DMC), 39.7 wt% of a flame retardant (composed of triethyl phosphate, trimethyl phosphate, and triphenyl phosphate in a mass ratio of 8:1:1), and 5 wt% of a film-forming additive (2.5 wt% VC, 1.4 wt% FEC, 0.8 wt% DTD, and 0.3 wt% MMDS).
[0059] Comparative Example 3 The difference between this comparative example and Example 1 is that the content of film-forming additives in one electrolyte is 2.5 wt%, specifically including 1 wt% VC, 0.5 wt% FEC, 0.5 wt% DTD and 0.5 wt% MMDS.
[0060] Comparative Example 4 The difference between this comparative example and Example 1 is that the content of film-forming additives in one electrolyte is 7 wt%. Specifically, it includes 3 wt% VC, 2.5 wt% FEC, 1 wt% DTD, and 0.5 wt% MMDS. Comparative Example 5 The difference between this comparative example and Example 1 is that the content of flame retardant component in the electrolyte of the second sample is 35wt%.
[0061] Comparative Example 6 The difference between this comparative example and Example 1 is that the content of flame retardant component in the electrolyte of the second sample is 60wt%.
[0062] Application examples The electrolytes provided in Examples 1-5 and Comparative Examples 1-6 were injected in the following manner to obtain different pouch batteries.
[0063] The preparation method of pouch cells is as follows: S1: Lithium iron phosphate powder is mixed with conductive agent (conductive carbon black), binder (polyvinylidene fluoride, PVDF) and solvent (N-methylpyrrolidone, NMP) in a ratio of 98.1%:0.3%:1.5%:0.1% to obtain a positive electrode slurry. The slurry is coated on aluminum foil and then dried, rolled, slit and die-cut to obtain a positive electrode sheet.
[0064] S2: Graphite is used as the main negative electrode material and is mixed with conductive agent, binder and dispersant in a ratio of 97%:0.5%:1.8%:0.7%. The mixture is homogenized with deionized water to obtain a negative electrode slurry. The negative electrode slurry is coated on carbon-coated copper foil and then dried, rolled, slit and die-cut to obtain a negative electrode sheet.
[0065] S3: The positive electrode, separator (PP film), and negative electrode are stacked in sequence, with the separator acting as an separator between the positive and negative electrodes. Then, the pouch cell is manufactured through a process of stacking, hot pressing, baking, primary electrolyte injection, high-temperature settling, formation, aging, secondary electrolyte injection, capacity testing, and OCV. The pouch cell has a capacity of 5Ah, a height of 7.6cm, and a thickness of 7.3mm; the electrolyte injection ratio (primary to secondary) is 9:1, and the electrolyte injection coefficient is 3.5g / Ah.
[0066] The above-mentioned pouch batteries were subjected to first-efficiency test, electrolyte quenching time test, high temperature 45℃ cycle test (to determine the capacity retention rate after 500 cycles), and hot box test. The test results are shown in Table 1.
[0067] Table 1 Test Results
[0068] As can be seen from Table 1, the electrolytes provided in Examples 1 to 5 of the present invention can all achieve good electrochemical and flame-retardant effects, with the electrolyte in Example 1 showing the best effect.
[0069] In Comparative Example 1, when flame retardant components were added to an electrolyte solution, a large number of phosphate ester molecules were co-embedded between the graphite layers along with lithium ions, causing the graphite to expand and peel off, resulting in poor film quality, high impedance, and seriously affecting the cell performance and flame retardant effect.
[0070] In Comparative Example 2, the addition of film-forming additives to the two-electrode electrolyte increased side reactions, subsequent film-forming impedance, and electrolyte system viscosity, severely affecting electrochemical performance and flame retardant effect.
[0071] In Comparative Examples 3-4, the improper amount of film-forming additives in the electrolytes resulted in the electrolytes failing to possess both good electrochemical performance and flame-retardant properties.
[0072] The improper amount of flame retardant components in the electrolytes of Comparative Examples 5 and 6 resulted in the electrolytes failing to possess both good electrochemical and flame retardant properties.
[0073] In summary, this invention effectively improves the compatibility between the electrolyte and electrode materials by adding suitable film-forming additives to the first electrolyte and performing film-forming treatment. This prevents some flame-retardant additives from being directly reduced and decomposed on the graphite negative electrode surface, thereby improving the battery's charge-discharge performance. Simultaneously, the use of phosphate ester compounds as flame-retardant components in the second electrolyte maintains good flame-retardant effects without reducing conductivity, effectively solving the problem of flame-retardant additives affecting battery charge-discharge performance in existing technologies. Therefore, the electrolyte provided by this invention has excellent thermal stability and flame retardancy, effectively reducing the risk of lithium-ion battery decomposition under abuse conditions such as overcharging and high temperatures, and improving battery safety and stability. Furthermore, the preparation method of the above electrolyte is simple and feasible, the raw materials are readily available, and the cost is moderate, showing good prospects for industrial application.
[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. An electrolyte, characterized in that, Includes one-cell and two-cell electrolyte solutions; The electrolyte solution includes a first lithium salt, a first organic solvent, and a film-forming additive. The second electrolyte comprises a second lithium salt, a flame retardant component, and a second organic solvent; the flame retardant component comprises at least one of a phosphate ester compound and a phosphite ester compound.
2. The electrolyte according to claim 1, characterized in that, Based on the total mass of one electrolyte injection as 100%, the electrolyte injection includes 3wt% to 5wt% of the film-forming additive; Preferably, the film-forming additive includes at least one of VC, FEC, DTD, MMDS and PS.
3. The electrolyte according to claim 1 or 2, characterized in that, Based on the total mass of the two electrolyte injections being 100%, the two electrolyte injections contain 40wt% to 55wt% flame-retardant components; Preferably, the flame retardant component includes phosphate ester compounds and phosphite compounds; wherein the phosphate ester compounds include at least one of trimethyl phosphate, triethyl phosphate, and triphenyl phosphate; and the phosphite compounds include at least one of trimethyl phosphite, triethyl phosphite, and tris(2,2,2-trifluoroethyl) phosphite.
4. The electrolyte according to claim 3, characterized in that, Based on the total mass of one electrolyte injection being 100%, the electrolyte injection further includes 6wt% to 35wt% of the first lithium salt; Preferably, the first lithium salt includes at least one of LiPF6, LiFSI, and LiTFSI.
5. The electrolyte according to claim 3, characterized in that, Based on the total mass of one electrolyte injection being 100%, the electrolyte injection further includes 60wt% to 91wt% of the first organic solvent; Preferably, the first organic solvent comprises at least one of linear carbonates and cyclic carbonates, wherein the linear carbonates comprise at least one of DMC and EMC, and the cyclic carbonates comprise EC.
6. The electrolyte according to claim 3, characterized in that, Based on the total mass of the two electrolytes being 100%, the two electrolytes also include 6wt% to 35wt% of the second lithium salt; Preferably, the second lithium salt comprises at least one of LiPF6, LiFSI, and LiTFSI.
7. The electrolyte according to claim 3, characterized in that, Based on the total mass of the two electrolyte injections being 100%, the two electrolyte injections also include 10wt% to 54wt% of a second organic solvent; Preferably, the second organic solvent comprises at least one of linear carbonates and cyclic carbonates, wherein the linear carbonates comprise at least one of DMC and EMC, and the cyclic carbonates comprise EC.
8. The electrolyte according to claim 1, characterized in that, The mass ratio of the first electrolyte injection to the second electrolyte injection is 7:3 to 9:
1.
9. A lithium-ion battery, characterized in that, Includes the electrolyte as described in any one of claims 1 to 8.
10. A method for preparing a lithium-ion battery as described in claim 9, characterized in that, The process includes the following steps: stacking the positive electrode, separator, and negative electrode in sequence, followed by stacking, hot pressing, baking, injecting the first electrolyte, high-temperature standing, formation, aging, injecting the second electrolyte, and capacity testing.