Use of a novel compound in an electrolyte containing a novel lithium salt

Abstract

This invention discloses the application of a novel compound in a novel lithium salt electrolyte. The application includes adding the novel compound with the structure shown in formula (I) to the electrolyte, wherein the definitions of R1, R2, R3, R4, R5, and R6 are detailed in the specification. After being added to the electrolyte, the novel compound forms a passivation layer containing B-F insoluble salts on the surface of the aluminum current collector, thereby inhibiting corrosion. This invention has advantages such as inhibiting aluminum current collector corrosion, suppressing gas generation and impedance growth during high-temperature battery storage, and improving cycle stability.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery electrolytes, and particularly to the application of a novel compound in electrolytes containing novel lithium salts. Background Technology

[0002] Electrolytes are generally composed of lithium salts, solvents, and functional additives, playing a crucial role in ionic conduction and electronic insulation between the positive and negative electrodes of a battery. Lithium hexafluorophosphate (LiPF6) is currently the main commercially available lithium salt, meeting the basic requirements for electrolyte production and use. However, its poor thermal stability and susceptibility to hydrolysis remain major bottlenecks hindering its continued application. Lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium fluorosulfonate (LiFSO3), as novel lithium salts, offer better conductivity, higher electrochemical and thermal stability, and hydrolysis resistance compared to lithium hexafluorophosphate (LiPF6). However, these compounds corrode aluminum current collectors, especially at potentials exceeding 3.6V. + LiS forms stable and highly soluble compounds with aluminum current collectors, such as LiFSI, which forms easily soluble Al(FSI)3 with aluminum current collectors. This continuously corrodes the aluminum current collector, causing internal short circuits and exacerbating performance degradation. In addition, new lithium salts such as LiFSI, LiTFSI, and LiFSO3 can lead to gas generation and deterioration of battery cycle storage performance.

[0003] Lithium hexafluorophosphate (LiPF6) hydrolyzes to produce HF, which can form AlF3 passivation on the aluminum current collector surface. Simultaneously, the decomposition produces PF5, which can also react with Al2O3 on the aluminum current collector surface to form AlF3 passivation. Therefore, in systems where LiPF6 is used as the primary lithium salt, aluminum current collector corrosion is generally not an issue. However, in electrolyte systems with high LiFSI or LiTFSI content or where LiPF6 is used as the primary lithium salt, LiPF6 is insufficient to suppress aluminum current collector corrosion.

[0004] Currently, the main compounds used to inhibit the corrosion of aluminum current collectors by LiFSI, LiTFSI, and LiFSO3 are lithium bis(oxalateborate)borate (LiBOB) and lithium difluorooxalateborate (LiDFOB). These boron-containing oxalates can decompose on the cathode surface to produce AlBO3, which passivates the aluminum current collector and inhibits its continued corrosion. However, due to the presence of oxalate, LiBOB and LiDFOB are prone to decomposition to produce CO2, which aggravates battery gas production. Furthermore, they have low solubility in conventional carbonate electrolytes, and the addition amount is less than 1.0%, so the corrosion inhibition effect is not obvious.

[0005] Although LiPF6 can form AlF3 passivated aluminum current collectors, it is also prone to hydrolysis, generating a large amount of HF, which degrades battery storage and cycle stability.

[0006] Therefore, it is essential to propose a method to effectively suppress corrosion of aluminum current collectors, while simultaneously inhibiting gas generation and impedance growth during high-temperature battery storage and improving battery cycle performance. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes the application of a novel compound in electrolytes containing novel lithium salts.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] The application of a novel compound in a novel lithium salt electrolyte, specifically, the addition of a novel compound with the structure shown in formula (I) to the electrolyte:

[0010]

[0011] In the formula, R1 and R2 are independently selected from fluorine, C1-C6 alkyl, and C1-C6 fluoroalkyl; R3, R4, R5, and R6 are independently selected from hydrogen, fluorine, C1-C6 alkyl, C1-C6 haloalkyl, C2-C6 alkenyl, or C2-C6 alkynyl.

[0012] The novel compound accounts for 0.1 to 10.0 wt% of the total mass of the electrolyte, preferably 0.5 to 4.0 wt%.

[0013] Preferably, the novel compound is selected from at least one of the following structures:

[0014]

[0015]

[0016] When added to the electrolyte, the novel compound forms a passivation layer containing BF insoluble salts, such as Al(BF4)3, on the surface of the aluminum current collector, thereby inhibiting corrosion. Furthermore, the novel compound can preferentially reduce and form a stable SEI film, which can suppress gas generation during high-temperature battery storage, impedance growth, and improve cycle stability.

[0017] This invention has found that when a novel lithium salt is used as the sole main salt, and the ratio of the novel compound to the novel lithium salt is between 1:6 and 1:3, corrosion of the aluminum current collector in lithium-ion batteries can be significantly inhibited. When lithium hexafluorophosphate is added to the novel lithium salt, and the total amount of the novel compound and lithium hexafluorophosphate added is not less than one-quarter of the amount of novel lithium salt added, and the amount of the novel compound is between 0.5% and 4%, this method can significantly inhibit corrosion of the aluminum current collector in lithium-ion batteries and further improve high-temperature storage and cycle performance.

[0018] In a specific embodiment, the amount of the novel lithium salt added to the electrolyte is 0.1% to 30.0% of the total mass of the electrolyte, preferably 5.0% to 15.0 wt%. The amount of the novel compound added is 0.1% to 10.0 wt% of the total mass of the electrolyte, preferably 0.5% to 4.0 wt%. The amount of lithium hexafluorophosphate added is 0% to 20.0 wt% of the total mass of the electrolyte, preferably 0% to 10.0 wt%.

[0019] In the application of the aforementioned novel compounds in lithium-ion batteries, the electrolyte also includes a basic additive selected from at least one of 1,3-propanesulfonate lactone, 1,3-propenesulfonate lactone, vinyl sulfate, 4-methylvinyl sulfate, 4,4'-divinyl sulfate, vinylene carbonate, fluorovinyl carbonate, vinyl ethylene carbonate, tris(trimethylsilane) phosphate, tris(trimethylsilane) borate, ethoxypentafluorocyclotriphosphononitrile, lithium difluorophosphate, lithium tetrafluoroborate, lithium bis(oxalate)borate, lithium difluorooxalateborate, and lithium difluorodioxalate phosphate.

[0020] In the application of the aforementioned novel compounds in lithium-ion batteries, the electrolyte also includes an organic solvent, which is selected from at least one of C3-C6 carbonate compounds, C3-C8 carboxylic acid ester compounds, sulfone compounds, and ether compounds.

[0021] Further, the C3-C6 carbonate compounds are selected from at least one of ethylene carbonate, propylene carbonate, butene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate; the C3-C8 carboxylic acid ester compounds are selected from at least one of γ-butyrolactone, methyl acetate, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, ethyl butyrate, propyl acetate, and propyl propionate; the sulfone compounds are selected from at least one of sulfolane, dimethyl sulfoxide, dimethyl sulfone, and diethyl sulfone; and the ether compounds are selected from triethylene glycol dimethyl ether and / or tetraethylene glycol dimethyl ether.

[0022] The present invention also provides a lithium-ion battery electrolyte, the electrolyte comprising:

[0023] The novel lithium salt is added at a rate of 0.1% to 30.0 wt% of the total mass of the electrolyte, preferably 5.0% to 15.0 wt%.

[0024] The novel compound is added at a concentration of 0.1 to 10.0 wt% of the total mass of the electrolyte, preferably 0.5% to 4.0 wt%.

[0025] Lithium hexafluorophosphate is added at a rate of 0 to 20.0 wt% of the total mass of the electrolyte, preferably 0% to 10.0 wt%.

[0026] The aforementioned basic additives; and at least one of the aforementioned organic solvents.

[0027] In some specific embodiments, the electrolyte is composed of novel compounds, novel lithium salts, basic additives, and organic solvents, with the ratio of the novel compounds to the novel lithium salts being between 1:6 and 1:3. In these electrolytes, the novel compounds can inhibit aluminum current collector corrosion caused by the novel lithium salts. Furthermore, the novel compounds can preferentially reduce and form a stable SEI film, suppressing gas generation and impedance growth during high-temperature battery storage and improving cycle stability.

[0028] In other specific embodiments, the electrolyte is composed of lithium hexafluorophosphate, a novel compound, a novel lithium salt, basic additives, and an organic solvent. The total amount of the novel compound and lithium hexafluorophosphate added is not less than one-quarter of the amount of the novel lithium salt added, and the amount of the novel compound added is between 0.5% and 4%. In this embodiment, the combined use of lithium hexafluorophosphate and the novel compound can inhibit the corrosion of the aluminum current collector in lithium-ion batteries and further improve high-temperature storage and cycle performance.

[0029] In some specific implementations, vinylene carbonate is used as a base additive, accounting for 0.1 to 5 wt% of the total electrolyte mass, which can suppress the impedance growth during the high-temperature storage of the battery.

[0030] In some specific implementations, 1,3-propanesulfonic acid lactone is used as a basic additive, accounting for 0.1 to 5 wt% of the total electrolyte mass, which can significantly suppress gas generation during high-temperature storage of the battery.

[0031] In some specific implementations, vinylene carbonate and lithium difluorophosphate are used as basic additives, accounting for 0.1 to 5 wt% of the total electrolyte mass, which can simultaneously improve the battery's high-temperature storage performance and high-temperature cycle performance.

[0032] In some specific implementations, vinyl sulfate and tris(trimethylsilane) phosphate are used as basic additives, accounting for 0.1 to 5 wt% of the total electrolyte mass, which can simultaneously improve the battery's high-temperature storage performance and high-temperature cycle performance.

[0033] In some specific implementations, vinylene carbonate, vinyl sulfate, and tris(trimethylsilane) phosphate are used as basic additives, accounting for 0.1 to 5 wt% of the total electrolyte mass, which can simultaneously improve the battery's high-temperature storage performance and high-temperature cycling performance.

[0034] In some specific embodiments, 1,3-propenesulfonate lactone and tris(trimethylsilane)borate ester are used as basic additives, accounting for 0.1 to 5 wt% of the total electrolyte mass, which can simultaneously improve the battery's high-temperature storage performance and high-temperature cycling performance.

[0035] In some specific implementations, vinyl ethylene carbonate and ethoxypentafluorocyclotriphosphonium are used as basic additives, accounting for 0.1 to 5 wt% of the total electrolyte mass, which can simultaneously improve the battery's high-temperature storage performance and high-temperature cycling performance.

[0036] The present invention also provides a lithium-ion battery, comprising a positive electrode, a negative electrode, a separator, and the electrolyte described above.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] This invention suppresses aluminum current collector corrosion caused by high concentrations of novel lithium salts by adding novel compounds. Higher concentrations of the novel lithium salts exhibit high ionic conductivity, reducing battery impedance. The novel compounds not only suppress aluminum current collector corrosion but also preferentially reduce and form a stable SEI film, inhibiting gas generation and impedance growth during high-temperature storage and improving cycle stability. When the novel compounds are used in conjunction with lithium hexafluorophosphate, corrosion suppression is further enhanced. Furthermore, the presence of the novel compounds reduces the amount of lithium hexafluorophosphate used, decreasing HF generation, lowering electrolyte acidity, and mitigating the deteriorating effect of HF on battery performance, ultimately further enhancing battery storage and cycle performance. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0040] I. Electrolyte Preparation

[0041] Example 1

[0042] In an argon-filled glove box (moisture content < 5 ppm, oxygen content < 10 ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were uniformly mixed in a mass ratio of EC:EMC:DEC = 3:5:2. Lithium bis(fluorosulfonyl)imide (LiFSI) was slowly added to the mixed solution until the mass fraction of LiFSI reached 12%. Then, compound A1, accounting for 3% of the electrolyte mass fraction, was added to obtain the electrolyte of this embodiment.

[0043] Example 2

[0044] The operation of this embodiment is the same as that of embodiment 1, except that compound A2 is used to replace compound A1, while the amount added remains the same, to obtain the electrolyte of this embodiment.

[0045] Example 3

[0046] The operation of this embodiment is the same as that of embodiment 1, except that compound A3 is used to replace compound A1, while the amount added remains the same, to obtain the electrolyte of this embodiment.

[0047] Example 4

[0048] The operation in this embodiment is the same as in embodiment 1, except that compound A4 is used to replace compound A1, while the amount added remains the same, to obtain the electrolyte of this embodiment.

[0049] Example 5

[0050] The operation of this embodiment is the same as that of embodiment 1, except that the amount of compound A1 added is adjusted to 2% to obtain the electrolyte of this embodiment.

[0051] Example 6

[0052] The operation of this embodiment is the same as that of embodiment 1, except that the amount of compound A1 added is adjusted to 4% to obtain the electrolyte of this embodiment.

[0053] Example 7

[0054] The operation of this embodiment is the same as that of Embodiment 1, except that the amount of lithium bis(fluorosulfonyl)imide (LiFSI) added is adjusted to 15% and the amount of compound A1 added is adjusted to 4%, thus obtaining the electrolyte of this embodiment.

[0055] Example 8

[0056] The operation of this embodiment is the same as that of Embodiment 1, except that the amount of lithium bis(fluorosulfonyl)imide (LiFSI) added is adjusted to 20% and the amount of compound A1 added is adjusted to 8%, thus obtaining the electrolyte of this embodiment.

[0057] Example 9

[0058] The operation of this embodiment is the same as that of embodiment 5, except that: based on embodiment 5, 1% vinylene carbonate (VC) is added to obtain the electrolyte of this embodiment.

[0059] Example 10

[0060] The operation of this embodiment is the same as that of embodiment 1, except that 1% of 1,3-propanesulfonic acid lactone (PS) is added on the basis of embodiment 1 to obtain the electrolyte of this embodiment.

[0061] Example 11

[0062] The operation of this embodiment is the same as that of embodiment 2, except that: based on embodiment 2, 1% vinylene carbonate (VC) and 1% lithium difluorophosphate (LiDFP) are added to obtain the electrolyte of this embodiment.

[0063] Example 12

[0064] The operation of this embodiment is the same as that of embodiment 3, except that: based on embodiment 3, 1% vinyl sulfate (DTD) and 1% tris(trimethylsilane) phosphate (TMSP) are added to obtain the electrolyte of this embodiment.

[0065] Example 13

[0066] The operation of this embodiment is the same as that of embodiment 4, except that: based on embodiment 4, 1% vinylene carbonate (VC), 1% vinyl sulfate (DTD) and 1% tris(trimethylsilane) phosphate (TMSP) are added to obtain the electrolyte of this embodiment.

[0067] Example 14

[0068] The operation of this embodiment is the same as that of embodiment 1, except that lithium bis(fluorosulfonyl)imide (LiTFSI) is used instead of lithium bis(fluorosulfonyl)imide (LiFSI), and the amount added remains the same, to obtain the electrolyte of this embodiment.

[0069] Example 15

[0070] The operation of this embodiment is the same as that of embodiment 1, except that lithium fluorosulfonate (LiFSO3) is used instead of lithium bisfluorosulfonylimide (LiFSI), and the amount added remains the same, to obtain the electrolyte of this embodiment.

[0071] Example 16

[0072] The operation of this embodiment is the same as that of embodiment 8, except that the amount of compound A1 is adjusted to 4%, and 8% lithium hexafluorophosphate (LiPF6) is added to obtain the electrolyte of this embodiment.

[0073] Example 17

[0074] The operation of this embodiment is the same as that of embodiment 7, except that the amount of compound A1 is adjusted to 2% and 6% lithium hexafluorophosphate (LiPF6) is added to obtain the electrolyte of this embodiment.

[0075] Example 18

[0076] The operation of this embodiment is the same as that of Embodiment 1, except that the amount of compound A1 is adjusted to 1%, and 4% lithium hexafluorophosphate (LiPF6) is added to obtain the electrolyte of this embodiment.

[0077] Example 19

[0078] The operation of this embodiment is the same as that of Embodiment 1, except that the amount of compound A1 is adjusted to 1%, and 3% lithium hexafluorophosphate (LiPF6) is added to obtain the electrolyte of this embodiment.

[0079] Example 20

[0080] The operation of this embodiment is the same as that of Embodiment 1, except that: based on Embodiment 1, the amount of compound A1 is adjusted to 0.5%, and 2.5% lithium hexafluorophosphate (LiPF6) is added to obtain the electrolyte of this embodiment.

[0081] Example 21

[0082] The operation of this embodiment is the same as that of embodiment 1, except that 1% lithium hexafluorophosphate (LiPF6) is added to obtain the electrolyte of this embodiment.

[0083] Example 22

[0084] The operation of this embodiment is the same as that of embodiment 18, except that: based on embodiment 18, 1% 1,3-propenesulfonate lactone (PST) and 1% tris(trimethylsilane)borate ester (TMSB) are added to obtain the electrolyte of this embodiment.

[0085] Example 23

[0086] The operation of this embodiment is the same as that of embodiment 18, except that: based on embodiment 18, 1% vinyl ethylene carbonate (VEC) and 1% ethoxypentafluorocyclotriphosphonium (PFPN) are added to obtain the electrolyte of this embodiment.

[0087] Comparative Example 1

[0088] The operation of this comparative example is the same as that of Example 1, except that the amount of compound A1 is adjusted to 0.5% to obtain the electrolyte of this comparative example.

[0089] Comparative Example 2

[0090] The operation of this comparative example is the same as that of Example 1, except that the amount of compound A1 is adjusted to 1% to obtain the electrolyte of this comparative example.

[0091] Comparative Example 3

[0092] The operation of this comparative example is the same as that of Example 1, except that 3% of compound A1 is not added to obtain the electrolyte of this comparative example.

[0093] Comparative Example 4

[0094] The operation of this comparative example is the same as that of Example 14, except that 3% of compound A1 is not added to obtain the electrolyte of this comparative example.

[0095] Comparative Example 5

[0096] The operation of this comparative example is the same as that of Example 15, except that 3% of compound A1 is not added to obtain the electrolyte of this comparative example.

[0097] Comparative Example 6

[0098] The operation of this comparative example is the same as that of Example 16, except that 4% of compound A1 is not added to obtain the electrolyte of this comparative example.

[0099] Comparative Example 7

[0100] The operation of this comparative example is the same as that of Example 18, except that 1% of compound A1 is not added to obtain the electrolyte of this comparative example.

[0101] Comparative Example 8

[0102] The operation of this comparative example is the same as that of Example 20, except that 0.5% of compound A1 is not added to obtain the electrolyte of this comparative example.

[0103] Comparative Example 9

[0104] The operation of this comparative example is the same as that of Example 21, except that 3% of compound A1 is not added to obtain the electrolyte of this comparative example.

[0105] Comparative Example 10

[0106] The operation of this comparative example is the same as that of Example 18, except that the amount of compound A1 is adjusted to 0.2% to obtain the electrolyte of this comparative example.

[0107] Comparative Example 11

[0108] The operation of this comparative example is the same as that of Example 20, except that the amount of lithium hexafluorophosphate (LiPF6) is adjusted to 1% to obtain the electrolyte of this comparative example.

[0109] II. Electrochemical Performance Testing

[0110] The performance of the lithium-ion power batteries (soft-pack cells) prepared in the examples and comparative examples was tested, mainly including:

[0111] (1) 60℃ high temperature storage test and aluminum foil corrosion verification: The battery was charged to 100% SOC and stored in an oven at 60±2℃ for 7 days. The volume before and after storage was tested to obtain the volume expansion rate of the single cell before and after storage at 60℃. The DCR value after storage at room temperature was tested and the percentage value of the initial DCR was calculated and recorded as the discharge DCR change rate. After the test, the battery was disassembled and the aluminum foil corrosion was observed.

[0112] (2) 45℃ high temperature cycle test: The battery is cycled in an oven at 45±1℃ with a charge / discharge current of 1C / 1C. The discharge capacity is calculated every week. The cycle is stopped after 200 cycles, and the capacity retention rate after the cycle is calculated.

[0113] The test results are shown in Table 1 below:

[0114] Table 1. Electrochemical performance test results of batteries without LiPF6 electrolyte

[0115]

[0116]

[0117] Table 2. Electrochemical performance test results of batteries containing LiPF6 electrolyte.

[0118]

[0119]

[0120] According to the test results in Table 1 above, adding sufficient amounts of the novel compound to the electrolyte can effectively inhibit the corrosion of aluminum current collectors by LiFSI and LiTFSI, suppress gas generation during high-temperature storage of the battery and the increase of DCR internal resistance, and improve high-temperature cycling performance.

[0121] Comparing Examples 1-8 with Comparative Examples 1-3, it can be found that when the ratio of the amount of the novel compound added to the amount of the novel lithium salt added in the electrolyte is between 1:6 and 1:3, the corrosion of the aluminum current collector by the novel lithium salt can be effectively suppressed, and the gas generation during high-temperature storage of the battery and the increase of DCR internal resistance can be suppressed, and the high-temperature cycling performance can be improved.

[0122] Comparing Examples 1-5 and Examples 9-13, it can be found that using at least one of VC, PS, LiDFP, DTD, and TMSP as a base additive in the electrolyte can further improve high-temperature storage performance and / or high-temperature cycling performance.

[0123] Comparing Examples 14-15 with Comparative Examples 4-5 reveals that the novel compounds can also inhibit the corrosion of aluminum current collectors by LiTFSI and LiFSO3, and improve high-temperature storage and high-temperature cycling performance.

[0124] According to the test results in Table 2, when the new compound and lithium hexafluorophosphate are used together and the amount added is sufficient, in addition to inhibiting corrosion, it can further improve the high-temperature storage performance and high-temperature cycling performance of the battery.

[0125] Comparative Examples 16-21 and Comparative Examples 6-11 show that when the total amount of the novel compound and lithium hexafluorophosphate added is not less than one-quarter of the amount of the novel lithium salt added, and the amount of the novel compound added is between 0.5% and 4%, the corrosion of the aluminum current collector by the novel lithium salt can be effectively suppressed, and the gas generation and DCR internal resistance growth of the battery during high-temperature storage can be suppressed, and the high-temperature cycle performance can be improved.

[0126] Comparing Examples 22-23 with Example 18, it can be found that using at least one of PST, TMSB, VEC, and PFPN as a base additive in the electrolyte can further improve high-temperature storage performance and / or high-temperature cycling performance.

Claims

1. The application of a novel compound in a novel lithium salt electrolyte, characterized in that: A novel compound with the structure shown in formula (I) was added to the electrolyte: In the formula, R1 and R2 are independently selected from fluorine, C1-C6 alkyl, and C1-C6 fluoroalkyl; R3, R4, R5, and R6 are independently selected from hydrogen, fluorine, C1-C6 alkyl, C1-C6 haloalkyl, C2-C6 alkenyl, or C2-C6 alkynyl. The novel lithium salt is selected from at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium fluorosulfonate, and the amount added accounts for 0.1 to 30.0 wt% of the total mass of the electrolyte.

2. The application of the novel compound according to claim 1 in a novel lithium salt electrolyte, characterized in that: The novel compound accounts for 0.1 to 10.0 wt% of the total mass of the electrolyte.

3. The application of the novel compound according to claim 1 or 2 in a novel lithium salt electrolyte, characterized in that: R1 and R2 are independently selected from fluorine, C1-C2 alkyl, and C1-C2 fluoroalkyl; R3, R4, R5, and R6 are independently selected from fluorine, C1-C2 alkyl, and C2-C3 alkenyl.

4. The application of the novel compound according to claim 3 in a novel lithium salt electrolyte, characterized in that: The novel compound is selected from at least one of the following structures: 。 5. The application of the novel compound according to claim 2 in a novel lithium salt electrolyte, characterized in that: The novel compound accounts for 0.5 to 4.0 wt% of the total mass of the electrolyte; the novel lithium salt accounts for 5.0 to 15.0 wt% of the total mass of the electrolyte.

6. A lithium-ion battery electrolyte, characterized in that: The electrolyte comprises: Lithium hexafluorophosphate, added at a rate of 0–20.0 wt% of the total electrolyte mass; The novel compound according to any one of claims 1-4 is added in an amount of 0.1% to 10.0% of the total mass of the electrolyte; A novel lithium salt, added at a concentration of 0.1% to 30.0% of the total electrolyte mass; Organic solvents and basic additives; the basic additives are selected from at least one of 1,3-propanesulfonate lactone, 1,3-propenesulfonate lactone, vinyl sulfate, 4-methylvinyl sulfate, 4,4'-divinyl sulfate, vinylene carbonate, fluorovinyl carbonate, vinyl vinyl carbonate, tris(trimethylsilane) phosphate, tris(trimethylsilane) borate, ethoxypentafluorocyclotriphosphononitrile, lithium difluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium difluorooxalatoborate, and lithium difluorodi(oxalato)phosphate.

7. The electrolyte according to claim 6, characterized in that: The electrolyte is composed of the novel compound, basic additives, organic solvents and novel lithium salts, and the ratio of the amount of the novel compound to the amount of the novel lithium salt is between 1:6 and 1:

3.

8. The electrolyte according to claim 6, characterized in that: The electrolyte is composed of lithium hexafluorophosphate, novel compounds, basic additives, organic solvents and novel lithium salts. The amount of lithium hexafluorophosphate added accounts for 0.1 to 20.0 wt% of the total mass of the electrolyte, the amount of the novel compounds added accounts for 0.1 to 10.0 wt% of the total mass of the electrolyte, and the amount of the novel lithium salts added accounts for 0.1 to 30.0% of the total mass of the electrolyte.

9. The electrolyte according to claim 8, characterized in that: The total amount of the novel compound and lithium hexafluorophosphate added shall not be less than one-quarter of the amount of the novel lithium salt added, and the amount of the novel compound added shall be between 0.5% and 4%.

10. The electrolyte according to any one of claims 6-8, characterized in that: The organic solvent is selected from at least one of C3-C6 carbonate compounds, C3-C8 carboxylic acid ester compounds, sulfone compounds, and ether compounds.

11. A lithium-ion battery, comprising a positive electrode, a negative electrode, and a separator, characterized in that: The lithium-ion battery further includes the electrolyte as described in any one of claims 6-10.

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