A lithium-ion battery electrolyte and a lithium-ion battery

Abstract

This invention belongs to the field of lithium-ion battery technology, specifically relating to a lithium-ion battery electrolyte and a lithium-ion battery. The lithium-ion battery electrolyte incorporates a lithium borate compound with a specific structure. This lithium borate compound contains a sulfur-oxygen double bond group or a trimethylsilane structure. Specifically, the combination of the borate group (-BF2) with a sulfoxy group or with a silane group can inhibit the decomposition of LiPF6, improve solute stability, and enhance the battery's capacity retention performance during high-temperature storage. The sulfoxy group also improves the battery's high-temperature lifespan. Simultaneously, this compound can reduce and form a stable protective film on the negative electrode surface, improving the battery's cycle life. The silane groups can absorb water and HF from the electrolyte, thereby reducing side reactions and lowering the battery's internal resistance.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a lithium-ion battery electrolyte and a lithium-ion battery. Background Technology

[0002] In recent years, with the development of new energy technologies, lithium-ion power batteries for vehicles have placed higher demands on the performance of lithium-ion secondary batteries. In order to meet the requirements of long driving range and wide temperature range of electric vehicles, it is necessary to develop lithium-ion secondary batteries with higher energy density, better high-temperature cycle performance, and storage performance to meet the lifespan requirement of more than 10 years for vehicle power batteries.

[0003] The cycle life of a battery mainly depends on the degree to which the positive and negative electrodes retain their structure during cycling and the rate of electrolyte consumption, both of which are closely related to the interface layer between the positive and negative electrodes. A stable and robust interface layer is beneficial in two ways: firstly, it helps to better maintain the bulk and surface structure of the positive and negative electrodes, improving the battery's capacity retention rate; secondly, it helps to suppress the rapid reaction and consumption of the electrolyte, extending the battery's lifespan.

[0004] Introducing suitable additives into existing electrolytes to induce a more stable interface layer through oxidation, reduction, and decomposition is a scientific and simple method. For example, existing technology discloses a lithium-ion secondary battery electrolyte additive, lithium difluorooxalate borate, which exhibits good low-temperature performance, but its improvement in high-temperature performance remains insufficient.

[0005] However, high-energy-density lithium-ion secondary batteries typically use transition metal oxides with high nickel content (such as lithium nickel cobalt manganese oxide) and high voltages (e.g., a maximum operating voltage of 4.2V–4.4V). These materials are prone to interface degradation, particle breakage, and electrolyte oxidation at high temperatures, leading to rapid lifespan degradation at high temperatures. Furthermore, due to the scarcity of cobalt, cobalt-free lithium nickel manganese oxide is a promising material; however, this material suffers from drawbacks such as poor stability and poor high-current charge / discharge performance.

[0006] Therefore, it is essential to develop an electrolyte for lithium-ion batteries that is suitable for high-nickel (cobalt-free) cathode materials and whose performance can be significantly improved at both high and low temperatures. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art, such as the electrolyte being unsuitable for high-nickel (cobalt-free) cathode materials and insufficient improvement in high-temperature performance, thereby providing a lithium-ion battery electrolyte and a lithium-ion battery.

[0008] Therefore, the present invention provides the following technical solution:

[0009] This invention provides a lithium-ion battery electrolyte, comprising an organic solvent, a lithium salt, and an additive, wherein the additive has a structure as shown in Formula 1, Formula 2, or Formula 3:

[0010] Equation 1, where n = 1 - 6;

[0011] Equation 2, where n = 0 - 6;

[0012] Equation 3; where n = 0 - 6.

[0013] Optionally, the additive has the structure shown in Formula 4, Formula 5 or Formula 6:

[0014]

[0015] Optionally, the additive has a mass fraction of 0.01-5% based on the total mass of the electrolyte;

[0016] Optionally, the mass fraction of the additive is 0.1-2%.

[0017] Optionally, the organic solvent, based on the total mass of the electrolyte, includes cyclic carbonates and chain esters;

[0018] Optionally, the volume ratio of cyclic carbonates to chain esters in the organic solvent is 10:90 to 40:60.

[0019] Preferably, the cyclic carbonate includes any one or a combination of at least two of ethylene carbonate, propylene carbonate, butene carbonate, or γ-butyrolactone.

[0020] Preferably, the chain ester comprises any one or a combination of at least two of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, or ethyl butyrate.

[0021] Optionally, the organic solvent comprises 70-90% by mass of the total mass of the electrolyte.

[0022] Optionally, the lithium salt comprises 8-25% by mass based on the total mass of the electrolyte;

[0023] And / or, the lithium salt includes at least one of LiPF6, Li(FSO2)2N (LiFSI), Li(CF3SO2)2N (LiTFSI), LiPO2F2 or LiClO4.

[0024] LiFSI and LiTFSI are industry abbreviations, and their structures are shown below:

[0025]

[0026] Optionally, the additive further includes a second additive selected from at least one of unsaturated cyclic carbonate compounds, halogen-substituted cyclic carbonate compounds, sulfate compounds, sulfite compounds, sulfonyl lactone compounds, nitrile compounds, aromatic compounds, isocyanate compounds, phosphazene compounds, cyclic anhydride compounds, phosphite compounds, phosphate compounds, or borate compounds.

[0027] And / or, based on the total mass of the electrolyte, the second additive is 0.1% to 2% by mass.

[0028] Optionally, the cyclic carbonate compound containing unsaturated bonds is at least one of vinylene carbonate and vinyl ethylene carbonate;

[0029] And / or, the halogen-substituted cyclic carbonate compounds include fluoroethylene carbonate;

[0030] And / or, the sulfate compound is at least one of vinyl sulfate and propylene sulfate;

[0031] And / or, the sulfite compound is at least one of vinyl sulfite and propylene sulfite;

[0032] And / or, the sulfonyl lactone compound is at least one of 1,3-propanesulfonyl lactone and 1,4-butanesulfonyl lactone;

[0033] And / or, the nitrile compound is at least one selected from succinic anion, adiponitrile, and glutaronitrile;

[0034] And / or, the aromatic compound includes at least one of biphenyl, cyclohexylbenzene, and tert-butylbenzene;

[0035] And / or, the isocyanate compound is at least one of 1,4-butanediisocyanate and 1,6-hexanediisocyanate;

[0036] And / or, the phosphazene compound is at least one of ethoxypentafluorocyclotriphosphazene and hexafluorocyclotriphosphazene;

[0037] And / or, the cyclic anhydride compound is at least one of succinic anhydride, maleic anhydride, and glutaric anhydride;

[0038] And / or, the phosphite compound includes tris(trimethylsilyl)phosphite;

[0039] And / or, the phosphate compound includes tris(trimethylsilyl)phosphate;

[0040] And / or, the borate ester compound includes tris(trimethylsilyl)borates.

[0041] The present invention also provides a lithium-ion battery, wherein the above-described lithium-ion battery electrolyte is used.

[0042] Optionally, the lithium-ion battery further includes a positive electrode and a negative electrode.

[0043] In this invention, both the positive and negative electrode plates in the lithium-ion battery are conventional components in the field. Typically, and not specifically, the positive electrode plate includes a positive electrode material;

[0044] Preferably, the cathode material is selected from LiCoO2 and LiNi. x Co y Mn z O2, LiNi x Mn y O2, LiMn2O4, LiMnO2, Li2MnO4, Li 1+a Mn 1-x M x O2, LiCo 1-x M x O2, LiMn 1-x M x O4, Li2Mn 1-x Any one or more of transition metal layered oxides such as O4, preferably LiNi x Co y Mn z O2 and LiNi x Mn y O2; can also be selected from LiFePO4, LiMnPO4, LiCoPO4, LiFe 1- x M x The PO4 is any one or more transition metal phosphate compounds, preferably LiFePO4, wherein M is selected from any one of Ni, Co, Mn, Al, Cr, Mg, Zr, Mo, V, Ti, 0≤a<0.2, 0≤x, y, z≤1.

[0045] Preferably, the negative electrode sheet comprises a negative electrode material;

[0046] Preferably, the negative electrode material includes any one or a combination of at least two of the following: soft carbon, hard carbon, artificial graphite, natural graphite, lithium metal, silicon-carbon, and silicon-oxygen.

[0047] The technical solution of this invention has the following advantages:

[0048] The lithium-ion battery electrolyte provided by this invention incorporates a lithium borate compound with a specific structure of this invention. This lithium borate compound is either a lithium borate compound containing a sulfur-oxygen double bond group or a lithium borate compound containing trimethylsilane. The borate group (-BF2) and the sulfoxy group work together to inhibit the decomposition of LiPF6, improve solute stability, and enhance the battery's capacity retention performance during high-temperature storage. The sulfoxy group can also undergo oxidation or chemical reaction on the positive electrode surface during charging. This type of compound is stable at high voltages and can prevent further oxidation of electrolyte components on the positive electrode surface, thereby improving the battery's high-temperature lifespan. Simultaneously, this compound can reduce and form a stable protective film on the negative electrode surface, improving the battery's cycle life. The combination of borate groups (-BF2) and silane groups can inhibit the decomposition of LiPF6, improve solute stability, and enhance the capacity retention performance of the battery during high-temperature storage. Silane groups can react with LiPF6 in the electrolyte to generate small amounts of LiPO2F2 and trimethylsilyl fluoride products, which can form a film on the positive electrode surface, reducing side reactions between the positive electrode and the electrolyte, thereby improving the battery's high-temperature performance. Simultaneously, silane groups can absorb moisture and HF from the electrolyte, further reducing side reactions and lowering the battery's internal resistance. Detailed Implementation

[0049] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0050] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0051] Example 1

[0052] This embodiment provides an electrolyte, the specific composition of which is as follows:

[0053] The electrolyte contains 14% lithium hexafluorophosphate by mass (the molar concentration of lithium hexafluorophosphate in the electrolyte is approximately 1 mol / L), and uses a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) as the organic solvent, wherein EC, EMC, and DEC account for 31%, 39%, and 15% of the electrolyte by mass, respectively. In addition, the electrolyte contains an additive: a compound of formula 4, accounting for 1% of the total mass of the electrolyte.

[0054] Example 2

[0055] This embodiment provides an electrolyte, the specific composition of which is as follows:

[0056] The lithium hexafluorophosphate comprises 14% of the total mass of the electrolyte (the molar concentration of lithium hexafluorophosphate in the electrolyte is approximately 1 mol / L). A mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) is used as the organic solvent, wherein EC, EMC, and DEC account for 31%, 39%, and 15% of the electrolyte by mass, respectively. In addition, the electrolyte contains an additive: compound 5, comprising 1% of the total mass of the electrolyte.

[0057] Example 3

[0058] This embodiment provides an electrolyte, the specific composition of which is as follows:

[0059] The lithium hexafluorophosphate comprises 14% of the total mass of the electrolyte (the molar concentration of lithium hexafluorophosphate in the electrolyte is approximately 1 mol / L). A mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) is used as the organic solvent, with EC, EMC, and DEC accounting for 31%, 39%, and 15% of the electrolyte's mass, respectively. Furthermore, the electrolyte contains an additive: compound 6, comprising 1% of the total mass of the electrolyte.

[0060] Example 4

[0061] This embodiment provides an electrolyte that differs from Example 1 only in that the mass fraction of compound 4 is 0.1%, the mass fraction of methyl ethyl carbonate is increased by 0.9%, and other conditions and parameters are exactly the same as in Example 1.

[0062] Example 5

[0063] This embodiment provides an electrolyte that differs from Example 1 only in that the mass fraction of compound 4 is 2%, the mass fraction of methyl ethyl carbonate is reduced by 1%, and other conditions and parameters are exactly the same as in Example 1.

[0064] Example 6

[0065] This embodiment provides an electrolyte that differs from Example 3 only in that the mass fraction of compound 6 is 0.1% and the mass fraction of methyl ethyl carbonate is increased by 0.9%, while other conditions and parameters are exactly the same as in Example 3.

[0066] Example 7

[0067] This embodiment provides an electrolyte that differs from Example 3 only in that the mass fraction of compound 6 is 2% and the mass fraction of methyl ethyl carbonate is reduced by 1%, while the other conditions and parameters are exactly the same as in Example 3.

[0068] Example 8

[0069] This embodiment provides an electrolyte that differs from Example 1 only in that the mass fraction of methyl ethyl carbonate is reduced by 1%, and it also contains 1% by mass of vinyl sulfate (DTD).

[0070] Example 9

[0071] This embodiment provides an electrolyte that differs from Example 1 only in that the mass fraction of methyl ethyl carbonate is reduced by 1%, and it also contains 1% lithium difluorophosphate (LiPO2F2) by mass.

[0072] Example 10

[0073] This embodiment provides an electrolyte that differs from Example 1 only in that LiN(SO2F)2LiFSI is used as the lithium salt, and dimethyl carbonate (DMC) is used as the solvent instead of DEC in Example 1.

[0074] Comparative Example 1

[0075] The only difference between this comparative example and Example 1 is that the compound shown in Formula 4 is not added; all other conditions and parameters are exactly the same as in Example 1.

[0076] Comparative Example 2

[0077] The only difference between this comparative example and Example 1 is that lithium difluorooxalateborate is used instead of the compound shown in Formula 4; all other conditions and parameters are exactly the same as in Example 1.

[0078] Comparative Example 3

[0079] The only difference between this comparative example and Example 1 is that the compound shown below is used instead of the compound shown in Formula 4; all other conditions and parameters are exactly the same as in Example 1.

[0080]

[0081] Comparative Example 4

[0082] The only difference between this comparative example and Example 1 is that tris(trimethylsilane)borate (TMSB) is used instead of the compound shown in Formula 4; all other conditions and parameters are exactly the same as in Example 1.

[0083] Performance testing:

[0084] Lithium nickel manganese oxide (LiNi) is used as the positive electrode active material. 0.75 Mn 0.25O2), conductive carbon black (Cabolt, Super-P), and PVDF (Solvay, PVDF5130) were dissolved in N-methylpyrrolidone at a mass ratio of 94:3.0:3.0 to prepare a positive electrode slurry. The positive electrode slurry was then uniformly coated onto the current collector aluminum foil with a coating amount of 18 mg / cm². 2 After drying at 85°C, the material is cold-pressed, trimmed, cut into sheets, and slit. Then, it is dried under vacuum at 85°C for 4 hours, and the tabs are welded to produce the positive electrode sheet of a lithium-ion secondary battery that meets the requirements.

[0085] The negative electrode active material (hard carbon), conductive agent (Super-P), thickener (CMC, manufactured by Shenzhen Taineng, model CMC2000), and binder (SBR, manufactured by Shenzhen Taineng, model BM451B) were dissolved in deionized water at a mass ratio of 96.5:1.0:1.0:1.5 and mixed evenly to prepare a negative electrode slurry. The negative electrode slurry was then uniformly coated onto the current collector copper foil with a coating amount of 8.9 mg / cm². 2 After drying at 85°C, the material is cold-pressed, trimmed, cut into sheets, and slit. Then, it is dried under vacuum at 110°C for 4 hours, and the tabs are welded to produce the negative electrode sheet for a lithium-ion secondary battery that meets the requirements.

[0086] The positive electrode, negative electrode, and separator (PE film, Celgard, model 2400) were stacked to form a battery with a thickness of 8mm, a width of 60mm, and a length of 130mm. The battery was then vacuum-baked at 85°C for 10 hours, and the electrolytes of each embodiment and comparative example (7g) were injected. The battery was then left to stand for 24 hours. After that, it was charged to 4.3V with a constant current of 0.1C (200mA), and then charged at a constant voltage of 4.3V until the current dropped to 0.05C (100mA). Then it was discharged to 2.8V with a constant current of 0.1C (200mA). This charge-discharge cycle was repeated twice. Finally, it was charged to 3.8V with a constant current of 0.1C (200mA) to obtain a lithium-ion battery.

[0087] At 25°C, the prepared lithium-ion secondary battery was first charged to 4.3V with a constant current of 1C, then further charged to 0.05C with a constant voltage of 4.3V, and then discharged to 2.8V with a constant current of 1C. This discharge capacity is the discharge capacity of the lithium-ion secondary battery before high-temperature storage. Then, the lithium-ion secondary battery was charged to 4.3V with a constant current of 1C, and stored at 60°C for 30 days. After storage, the lithium-ion secondary battery was placed at 25°C, and then discharged to 2.8V with a constant current of 0.5C. After that, the lithium-ion secondary battery was charged to 4.3V with a constant current of 1C, then further charged to 1C with a constant voltage of 4.3V, and then discharged to 2.8V with a constant current of 1C. This final discharge capacity is the discharge capacity of the lithium-ion secondary battery after high-temperature storage. Capacity retention rate (%) of lithium-ion secondary battery after high-temperature storage = [Discharge capacity of lithium-ion secondary battery after high-temperature storage / Discharge capacity of lithium-ion secondary battery before high-temperature storage] × 100%.

[0088] The high-temperature cycle performance of the prepared lithium-ion secondary batteries was tested. The specific method was as follows: at 45℃, the lithium-ion secondary batteries were first charged to 4.3V with a constant current of 1C, then charged to 0.05C with a constant voltage of 4.3V, and finally discharged to 2.8V with a constant current of 1C. This constitutes one charge-discharge cycle, and the discharge capacity of this cycle is taken as the discharge capacity of the first cycle. The lithium-ion secondary batteries were subjected to charge-discharge tests in the above manner, and the discharge capacity of the 800th cycle was recorded.

[0089] High-temperature storage test: First, the battery volume was measured using the water displacement method; this is the volume before storage. Then, the lithium-ion battery was stored at 60℃ for 30 days. After storage, the lithium-ion secondary battery was placed in a 25℃ environment, and its volume was measured again using the water displacement method; this is the volume after storage. Next, the lithium-ion secondary battery was charged to 4.3V at a constant current of 1C, then further charged at a constant voltage of 4.3V to a current of 1C, and finally discharged to 2.8V at a constant current of 1C. The final discharge capacity is the discharge capacity of the lithium-ion secondary battery after high-temperature storage. Battery volume expansion rate = (volume after storage / volume before storage - 1)%.

[0090] DC internal resistance test: At 25℃, the lithium-ion secondary batteries prepared in each example and comparative example were first charged to 4.3V with a constant current of 1C. Then, they were further charged to a constant current of 0.05C with a constant voltage of 4.3V. Finally, the lithium-ion secondary batteries were discharged for 1 hour with a constant current of 0.5C, maintaining a state of charge (SOC) of 50%. After resting for 10 minutes, the voltage V1 was recorded. Then, the battery was discharged for 10 seconds with a current I (I = 5C), and the discharge termination voltage V2 was recorded. The DC internal resistance (DCIR) of the battery is calculated using the formula: DCIR = (V1 - V2) / I, in mΩ. The batteries were then cooled to -20℃ and allowed to rest for 60 minutes, after which the voltage V1 was recorded. Then, the battery was discharged for 10 seconds with a current I (I = 1C), and the discharge termination voltage V2 was recorded. The DC internal resistance (DCIR) of the battery is calculated using the formula: DCIR = (V1 - V2) / I, in mΩ.

[0091] Low-temperature performance: Following the previous step, cool the battery to -20°C and let it stand for 60 minutes, then record the voltage V1. At this point, discharge the battery with a current I (I = 1C) for 10 seconds and record the discharge termination voltage V2. The battery's discharge DC internal resistance (DCIR) is calculated using the formula: DCIR = (V1 - V2) / I, in mΩ.

[0092] High-current charging and discharging: At 25°C, the lithium-ion secondary batteries prepared in each example and comparative example were first charged to 4.3V with a constant current of 1C, and then charged to 0.05C with a constant voltage of 4.3V. Then, they were discharged with a constant current of 4C. The discharge capacity was recorded. The percentage of the 4C discharge capacity divided by the 1C discharge capacity was recorded as the high-current discharge capacity of the battery.

[0093] The test results are shown in Table 1:

[0094] Table 1

[0095]

[0096] As shown in Table 1, a comparison between Examples 1-3 and Comparative Example 1 reveals that the addition of lithium borate compound to the electrolyte forms a low-internal-resistance, stable SEI film on the positive and negative electrode surfaces, significantly improving the battery's high-temperature cycling and storage performance while reducing gas production. A comparison between Examples 4-5 and Example 1, and between Examples 6-7 and Example 3, shows that excessively low or high additive content can affect the additive's performance. A comparison between Examples 8-9 and Comparative Example 1 demonstrates that the lithium borate compound of this invention, when used in combination with additives such as ethylene sulfate (DTD) or lithium difluorophosphate (LiPO2F2), exhibits better performance. The compounds of this invention demonstrate superior high-temperature and low-temperature performance compared to the compounds mentioned in Comparative Examples 2-4.

[0097] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A lithium-ion battery electrolyte, characterized in that, It includes an organic solvent, a lithium salt, and an additive, said additive having the structure shown in Formula 3: Equation 3; where n = 0 - 6; The mass fraction of the additive shown in Formula 3 is 0.1-2% based on the total mass of the electrolyte; The organic solvents include cyclic carbonates and chain esters; The lithium salt includes LiPF6.

2. The lithium-ion battery electrolyte according to claim 1, characterized in that, The additive has the structure shown in Formula 6: Formula 6.

3. The lithium-ion battery electrolyte according to claim 1 or 2, characterized in that, The volume ratio of cyclic carbonates to chain esters in the organic solvent is 10:90 to 40:

60.

4. The lithium-ion battery electrolyte according to claim 1, characterized in that, The organic solvent accounts for 70-90% of the total mass of the electrolyte.

5. The lithium-ion battery electrolyte according to claim 1, characterized in that, The lithium salt comprises 8-25% by mass of the total mass of the electrolyte; And / or, the lithium salt further includes at least one of Li(FSO2)2N, Li(CF3SO2)2N, LiPO2F2, or LiClO4.

6. The lithium-ion battery electrolyte according to claim 1, characterized in that, The additive further includes a second additive selected from at least one of the following: cyclic carbonate compounds containing unsaturated bonds, halogen-substituted cyclic carbonate compounds, sulfate compounds, sulfite compounds, sulfonyl lactone compounds, nitrile compounds, aromatic compounds, isocyanate compounds, phosphazene compounds, cyclic anhydride compounds, phosphite compounds, phosphate compounds, or borate compounds.

7. The lithium-ion battery electrolyte according to claim 6, characterized in that, The second additive has a mass percentage of 0.1% to 2% based on the total mass of the electrolyte.

8. The lithium-ion battery electrolyte according to claim 6, characterized in that, The cyclic carbonate compound containing unsaturated bonds is at least one of vinylene carbonate and vinyl ethylene carbonate; And / or, the halogen-substituted cyclic carbonate compounds include fluoroethylene carbonate; And / or, the sulfate compound is at least one of vinyl sulfate and propylene sulfate; And / or, the sulfite compound is at least one of vinyl sulfite and propylene sulfite; And / or, the sulfonyl lactone compound is at least one of 1,3-propanesulfonyl lactone and 1,4-butanesulfonyl lactone; And / or, the nitrile compound is at least one selected from succinic anion, adiponitrile, and glutaronitrile; And / or, the aromatic compound includes at least one of biphenyl, cyclohexylbenzene, and tert-butylbenzene; And / or, the isocyanate compound is at least one of 1,4-butanediisocyanate and 1,6-hexanediisocyanate; And / or, the phosphazene compound is at least one of ethoxypentafluorocyclotriphosphazene and hexafluorocyclotriphosphazene; And / or, the cyclic anhydride compound is at least one of succinic anhydride, maleic anhydride, and glutaric anhydride; And / or, the phosphite compound includes tris(trimethylsilyl)phosphite; And / or, the phosphate compound includes tris(trimethylsilyl)phosphate; And / or, the borate ester compound includes tris(trimethylsilyl)borates.

9. A lithium-ion battery, characterized in that, Includes the lithium-ion battery electrolyte according to any one of claims 1-8.

10. The lithium-ion battery according to claim 9, characterized in that, The lithium-ion battery also includes a positive electrode and a negative electrode.

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