Lithium ion battery and electric device using the same

Abstract

The present application belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery and an electric device. The present application introduces a tetraether nitrile additive into the electrolyte of a silicon negative electrode battery, combines with a diisocyanate additive, controls the content of the silicon negative electrode material, ensures the improvement of the stability of the positive and negative electrode surfaces, utilizes the ether bond structure of the tetraether nitrile compound to transfer Li + during discharge, achieves the purpose of improving the rate discharge and low-temperature discharge performance, and thus improves the cycle performance of the high-voltage LiCoO2 and high-silicon negative electrode system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery and an electric device. BACKGROUND

[0002] Lithium ion batteries have the characteristics of high voltage, high safety and long cycle life, and play an important role in people's life. Lithium ion batteries are also developing towards high energy density, and the gravimetric capacity of positive and negative active materials is increasingly required. The gravimetric capacity of the positive electrode material can be improved mainly by increasing the voltage. At present, the voltage of LiCoO2 positive active material has been generally increased to 4.48V, and 4.53V and 4.55V materials have also been developed. High voltage brings high gravimetric capacity, but also brings problems such as reduction of stability of positive electrode material and electrolyte and deterioration of cycle life. Graphite, as the current mainstream negative active material, has a gravimetric capacity of 360-365mAh / g, which is basically close to the theoretical gravimetric capacity (372mAh / g), and it is difficult to improve further. Therefore, the most effective method at present is to develop new negative active materials. The negative active materials in the development stage at present mainly include tin-based materials, silicon-based materials, lithium titanate LTO, etc., among which the most promising is the silicon-based negative material. The silicon-based negative material has a theoretical gravimetric capacity of 4200mAh / g, which is much higher than that of graphite material, and the raw material source is abundant, and the cost can be reduced to a very low level after large-scale production. Therefore, all major lithium battery manufacturers are developing silicon-based negative batteries, or have development plans in the future. However, the silicon-based negative electrode also has some significant shortcomings, such as large volume change (150-300%) during charging and discharging, low initial efficiency, and corrosion of silicon particles by HF in the electrolyte. The traditional electrolyte has poor stability and is not suitable for the new positive and negative electrode system.

[0003] The application number 202310606579.5 discloses an electrolyte and a lithium ion battery, wherein the additive X contains hydroxyl and nitrile groups. Under high voltage working conditions, the hydroxyl group will undergo oxidative dehydrogenation reaction to produce hydrogen radicals, and the hydrogen radicals will capture oxygen radicals generated during phase change. The additive X has good oxidation resistance, and the additive X can form a uniform CEI film on the surface of the positive electrode material. Although it can alleviate the problem of decline of electrochemical performance of lithium ion batteries under high pressure, it cannot form a stable SEI on the surface of the silicon negative electrode to improve the cycle performance of the high-voltage LiCoO2 and high-silicon negative electrode system. SUMMARY

[0004] The present application provides a lithium ion battery to solve the above technical problems.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A lithium ion battery comprising a positive electrode, a negative electrode, and an electrolyte, the negative electrode active material of the negative electrode comprising a silicon negative electrode material, the content of the silicon negative electrode material being 10-30 wt% of the total weight of the negative electrode active material; the electrolyte comprising a lithium salt, an organic solvent, and a first additive, the first additive comprising an additive A having a structure of Formula I and an additive B having a structure of Formula II;

[0007]

[0008] (I)

[0009]

[0010] (II)

[0011] wherein R1-R6 are each independently selected from substituted or unsubstituted C1-C10 carbon atoms, alkylene or alkylidene; the content of the additive A being 0.05-5 wt% of the total amount of the electrolyte, and the content of the additive B being 0.03-8 wt% of the total amount of the electrolyte.

[0012] Preferably, the organic solvent comprises at least one of ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and propyl propionate (PP).

[0013] Preferably, the content of the additive A is 0.1-3 wt% of the total amount of the electrolyte, and the content of the additive B is 0.1-5 wt% of the total amount of the electrolyte.

[0014] Preferably, the additive A has a structure as shown in Formula (III):

[0015]

[0016] (III)

[0017] Preferably, the additive B has at least one of a structure as shown in Formula (IV) and Formula (V):

[0018]

[0019] (V)

[0020] Preferably, the lithium salt is selected from one or more of lithium hexafluorophosphate (LiPF6), lithium difluorophosphate (LiDFP), lithium difluorobisoxalate phosphate (LiODFP), lithium tetrafluorooxalate phosphate (LiOTFP), lithium bisoxalate borate (LiBOB), lithium difluorooxalate borate (LiODFB), lithium tetrafluoroborate (LiBF4), lithium bis-trifluoromethanesulfonylimide (LiTFSI), and lithium bisfluorosulfonylimide (LiFSI).

[0021] Preferably, the lithium salt compound content is 0.1-25wt% of the total mass of the electrolyte.

[0022] Preferably, a second additive is further included, the second additive including one or several of 1,3,6-hexanetricarbonitrile (HTCN), adiponitrile (ADN), 1,3-propanesultone (PS), vinyl sulfate (DTD), fluoroethylene carbonate (FEC), tris(trimethylsilyl)borate (TMSB), and tris(trimethylsilyl)phosphate (TMSP).

[0023] Preferably, the mass of the second additive is 0.1-20wt% of the total mass of the electrolyte.

[0024] The application further aims to provide an electric device made of the above lithium ion battery.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] By introducing the tetraether nitrile additive into the electrolyte and combining with the diisocyanate additive, the ether bond structure of the tetraether nitrile compound is utilized to transfer Li + under the premise of ensuring the improvement of the positive and negative electrode surface stability, the performance of the high-rate discharge and the low-temperature discharge is improved. When the voltage of the positive electrode is higher than 4.45V, the phenomenon of transition metal ion dissolution usually occurs, and with the increase of the voltage, the transition metal ion dissolution is intensified. In theory, the aprotic solvent used in the electrolyte will be oxidized when the voltage is higher than 6V, but under the influence of the low solvent purity and the catalytic effect of the transition metal ion, the electrolyte solvent will be oxidized when the voltage is higher than 4.45V, and the higher the voltage, the more serious the electrolyte solvent oxidation. The oxidation potential of the nitrile compound is as high as 6.7V, and the addition of the nitrile compound as the electrolyte additive can effectively reduce the oxidation of the electrolyte under high voltage and effectively improve the cycle performance of the battery under high voltage. And the cyano group (-CN) of the nitrile compound can effectively complex with Co ion, effectively reducing the negative reaction of the electrolyte. The ether bond contained in the structure of the tetraether nitrile compound can transfer Li + , and the discharge performance is obviously better than that of the aliphatic nitrile. The isocyanate can form a polymer SEI on the surface of the positive and negative electrodes, which can effectively protect the positive and negative active materials and maintain high stability during the cycle process, reducing the volume change and Li +The SEI rupture caused by deintercalation. At the same time, the -NCO group of isocyanate can react with H2O and HF in the electrolyte, reducing the lithium salt decomposition and positive transition metal ion dissolution caused by the two, while inhibiting the corrosion of HF to the negative silicon material, prolonging the cycle life of the battery. Under high temperature environment and long time cycle conditions, H2O in the electrolyte will react with LiPF6 to cause the decomposition of the latter, generating HF and PF5, and PF as a Lewis acid will also catalyze the continuous decomposition of LiPF6, forming a chain reaction, which worsens the cycle performance and increases the impedance. The specific reaction is shown below:

[0027]

[0028] Therefore, by adding isocyanate, the chain reaction can be blocked, and the hydrolysis of LiPF6 can be prevented, which can effectively prolong the cycle life of lithium ion battery.

[0029] The amount of silicon doping suitable for the present solution is 10-30 wt%, that is, only when the content of silicon negative electrode material is 10-30 wt% of the total weight of the negative electrode active material, the additive A and the additive B can play a role, and together improve the cycle performance and other key performances of the silicon negative electrode system. When the amount of silicon doping is less than 10 wt%, the negative electrode system has no obvious difference compared with the ordinary graphite system, and the additive combination has a small improvement effect on the system. When the amount of silicon doping is higher than 30 wt%, the volume change during the charging and discharging process of the silicon negative electrode is too large, and the stability of SEI is seriously deteriorated, and the additive combination also cannot improve the stability of SEI. DETAILED DESCRIPTION

[0030] The present application will be further described in detail below in conjunction with specific examples, but the embodiments of the present application are not limited thereto.

[0031] Example 1

[0032] Preparation of electrolyte:

[0033] In an argon-filled glove box, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and propyl propionate (PP) were mixed in a mass ratio of 2:2:3:3 to obtain a solvent, then 14 wt% of lithium hexafluorophosphate (LiPF6) based on the total weight of the electrolyte was slowly added to the solvent, and finally 2.5 wt% of additive A, 2.5 wt% of additive B, 4 wt% of 1,3-propanesultone (PS), and 1 wt% of tris(trimethylsilyl)borate (TMSB) based on the total weight of the electrolyte were added, and stirred uniformly to obtain a lithium ion battery electrolyte.

[0034] The structure of additive A is as follows:

[0035]

[0036] Additive B has the following structure:

[0037]

[0038] Preparation of the positive electrode sheet:

[0039] The positive electrode film includes positive active material lithium cobalt oxide (LiCoO2), conductive agent (Super P), and binder polyvinylidene fluoride (PVDF), which are mixed in a weight ratio of 97:1.7:1.3, then added into N-methyl pyrrolidone (NMP) to prepare a lithium ion battery positive electrode slurry. The positive electrode slurry is coated on the current collector aluminum foil, dried at 85°C, then cold-pressed, followed by edge cutting, sheet cutting, and striping, and then dried at 85°C under vacuum for 4h, and the tab is welded to prepare the lithium ion battery positive electrode sheet.

[0040] Preparation of the negative electrode sheet:

[0041] The negative electrode film includes negative active material graphite and SiC (or SiO x ), conductive agent carbon nanotube (CNT), thickening agent sodium carboxymethyl cellulose (CMC), and binder polyacrylic acid (PAA). The graphite and SiC are mixed in a weight ratio of 80:20 as the negative active material. The materials are mixed in a weight ratio of negative active material: conductive agent carbon nanotube (CNT): thickening agent sodium carboxymethyl cellulose (CMC): binder polyacrylic acid (PAA) = 93.5:1.3:1.2:4, then added into deionized water to prepare a negative electrode slurry. The negative electrode slurry is coated on the current collector copper foil, dried at 85°C, then cold-pressed, followed by edge cutting, sheet cutting, and striping, and then dried at 85°C under vacuum for 12h to obtain the lithium ion battery negative electrode sheet.

[0042] Preparation of the lithium ion battery:

[0043] The prepared positive electrode sheet, separator, and negative electrode sheet are stacked in order with the separator between the positive and negative electrode sheets, and then wound to obtain a bare cell. The bare cell is placed in an aluminum plastic film outer package, and the electrolyte prepared above is injected into the dried battery, which is then packaged, left to stand, formed, shaped, and divided to complete the preparation of the lithium ion soft-pack battery.

[0044] Example 2: The difference from Example 1 is only that the content of additive A is 0.05wt% of the total weight of the electrolyte, and the total amount of the electrolyte is kept unchanged by adjusting the solvent content.

[0045] Example 3: The difference from Example 1 is only that the content of additive B is 0.03wt% of the total weight of the electrolyte, and the total amount of the electrolyte is kept unchanged by adjusting the solvent content.

[0046] Example 4: The difference from Example 1 is only that the content of additive A is 5wt% of the total weight of electrolyte, and the total amount of electrolyte is kept unchanged by adjusting the solvent content.

[0047] Example 5: The difference from Example 1 is only that the content of additive B is 8wt% of the total weight of electrolyte, and the total amount of electrolyte is kept unchanged by adjusting the solvent content.

[0048] Example 6: The difference from Example 1 is only that the content of additive A is 0.1wt% of the total weight of electrolyte, and the total amount of electrolyte is kept unchanged by adjusting the solvent content, and the upper limit of the voltage of the cathode active material is raised from 4.53V to 4.55V.

[0049] Example 7: The difference from Example 1 is only that the content of additive A is 3wt% of the total weight of electrolyte, and the total amount of electrolyte is kept unchanged by adjusting the solvent content.

[0050] Example 8: The difference from Example 1 is only that the content of additive B is 0.1wt% of the total weight of electrolyte, and the total amount of electrolyte is kept unchanged by adjusting the solvent content.

[0051] Example 9: The difference from Example 1 is only that the content of additive B is 5wt% of the total weight of electrolyte, and the total amount of electrolyte is kept unchanged by adjusting the solvent content.

[0052] Example 10: The difference from Example 1 is only that the structure of additive B is as follows:

[0053] .

[0054] Example 11: The difference from Example 1 is only that additive B is 2,6-toluene diisocyanate.

[0055] Example 12: The difference from Example 1 is only that the weight ratio of graphite and SiC is 90:10, and the total weight of the negative electrode active material remains unchanged.

[0056] Example 13: The difference from Example 1 is only that the weight ratio of graphite and SiC is 70:30, and the total weight of the negative electrode active material remains unchanged.

[0057] Comparative Example 1: The difference from Example 1 is only that no additive A is added, and the total amount of electrolyte is kept unchanged by adjusting the solvent content.

[0058] Comparative Example 2: The difference from Example 1 is only that no additive B is added, and the total amount of electrolyte is kept unchanged by adjusting the solvent content.

[0059] Comparative Example 3: The difference from Example 1 is only that the additive A is changed to adiponitrile, i.e. ADN, and the amount is unchanged, which is 2.5 wt% of the total weight of the electrolyte.

[0060] Comparative Example 4: The difference from Example 1 is only that the additive A is changed to 1,3,6-hexanetricarbonitrile, i.e. HTCN, and the amount is unchanged, which is 2.5 wt% of the total weight of the electrolyte.

[0061] Comparative Example 5: The difference from Example 1 is only that the weight ratio of graphite and SiC is 95:5, and the total weight of the negative active material remains unchanged.

[0062] Comparative Example 6: The difference from Example 1 is only that the weight ratio of graphite and SiC is 65:35, and the total weight of the negative active material remains unchanged.

[0063] Comparative Example 7: The difference from Example 1 is only that the content of the additive A is 0.02 wt% of the total weight of the electrolyte, and the total amount of the electrolyte is kept unchanged by adjusting the solvent content.

[0064] Comparative Example 8: The difference from Example 1 is only that the content of the additive A is 6 wt% of the total weight of the electrolyte, and the total amount of the electrolyte is kept unchanged by adjusting the solvent content.

[0065] Comparative Example 9: The difference from Example 1 is only that the content of the additive B is 0.02 wt% of the total weight of the electrolyte, and the total amount of the electrolyte is kept unchanged by adjusting the solvent content.

[0066] Comparative Example 10: The difference from Example 1 is only that the content of the additive B is 10 wt% of the total weight of the electrolyte, and the total amount of the electrolyte is kept unchanged by adjusting the solvent content.

[0067] Table 1 Process parameters of examples and comparative examples

[0068] Group Content of additive A / wt% Content of additive B / wt% Graphite:SiC (weight ratio) Example 1 2.50% 2.50% 80：20 Example 2 0.05% 2.50% 80：20 Example 3 2.50% 0.03% 80：20 Example 4 5.00% 2.50% 80：20 Example 5 2.50% 8.00% 80：20 Example 6 0.1% 2.50% 80：20 Example 7 3% 2.50% 80：20 Example 8 2.50% 0.10% 80：20 Example 9 2.50% 5% 80：20 Example 10 2.5% Example 11 80：20 Example 12 2.5% Example 13 80：20 Comparative Example 1 2.50% 2.50% 90：10 Comparative Example 2 2.50% 2.50% 70：30 Comparative Example 3 0.00% 2.50% 80：20 Comparative Example 4 2.50% 0.00% 80：20 Comparative Example 5 Comparative Example 6 2.50% 80：20 Comparative Example 7 Comparative Example 8 2.50% 80：20 Comparative Example 9 2.50% 2.50% 95：5 Comparative Example 10 2.50% 2.50% 65：35 Test item 0.02% 2.50% 80：20 Cycling at room temperature for 400 weeks, capacity retention rate / % 6% 2.50% 80：20 Cycling at high temperature for 300 weeks, capacity retention rate / % 2.50% 0.02% 80：20 Low temperature discharging capacity retention rate at -10℃ / % 2.50% 10% 80：20

[0069] The batteries prepared in Examples 1-13 and Comparative Examples 1-10 were subjected to relevant performance tests.

[0070] (1) Normal temperature cycle performance test: In a 25℃ environment, the battery after separation and distribution was charged to 4.53V at 0.7C constant current and constant voltage, and the cutoff current was 0.05C, then discharged to 3.0V at 0.5C constant current, and the cycle was repeated, and the capacity retention rate at the 400th cycle was calculated after 400 cycles of charge and discharge, and the calculation formula was as follows:

[0071] The capacity retention rate at the 400th cycle (%) = (the 400th cycle discharge capacity / the first cycle discharge capacity) x 100%.

[0072] (2) High temperature cycle performance test: in 45℃ environment, the battery after the division is charged to 4.53V at 0.7C constant current and constant voltage, the cutoff current is 0.05C, then discharged to 3.0V at 0.5C constant current, and so on, after 300 cycles of charging and discharging, the capacity retention rate of the 300th cycle is calculated, and the calculation formula is as follows:

[0073]

[0074] (3) 85℃ 24h high temperature storage test: the battery is charged and discharged at 0.5C (4.53V-3.0V) at room temperature once, the discharge capacity C0 before storage is recorded, then the battery is charged to 4.53V full state (100% SOC) at constant current and constant voltage, the thickness d1 of the battery before high temperature storage is tested using PPG battery thickness tester (600g), the battery is placed in 85℃ constant temperature oven for 24h, after storage, the battery thickness d2 after storage is tested, the thickness expansion rate of the battery after 85℃ storage for 24h is calculated; after the battery is cooled at room temperature for 24h, the battery is discharged to 3.0V at 0.5C constant current, then charged to 4.53V at 0.5C constant current and constant voltage, the discharge capacity C1 and the charge capacity C2 after storage are recorded, the capacity remaining rate and the recovery rate of the battery after 85℃ storage for 24h are calculated, and the calculation formula is as follows:

[0075]

[0076]

[0077]

[0078] (4) Low temperature discharge performance test: the battery is placed in a 25℃ oven for 2h, charged to 100% SOC at 0.2C constant current and constant voltage, the cutoff current is 0.02C, then discharged to 3.0V at 0.5C rate, and so on for 3 times, the capacity of the third discharge is taken as C0; the battery is charged to 100% SOC at 0.2C constant current and constant voltage, then placed in a-10℃ low temperature oven for 2h, then discharged to 3.0V at 0.2C current, the capacity C1 is obtained, the discharge capacity retention rate of the battery in-10℃ environment is calculated, and the calculation formula is as follows:

[0079]

[0080] Table 1 performance test results of examples and comparative examples

[0081] Table 1 performance test results of examples and comparative examples​​​​ Thickness expansion rate at 85℃ / 24h / % Capacity retention rate at 85℃ / 24h / % Capacity recovery rate at 85℃ / 24h / % Example 1 Example 2 Example 3 Example 4 Example 5 85.5% 84.6% 65.5% 1.2% 87.7% 92.0% Example 6 85.1% 84.5% 65.1% 1.0% 86.9% 91.7% Example 7 84.9% 84.3% 64.8% 1.5% 86.8% 91.8% Example 8 86.2% 85.6% 64.8% 0.7% 88.1% 92.8% Example 9 86.2% 85.2% 64.1% 1.2% 88.2% 91.8% Example 10 85.9% 85.3% 66.1% 1.0% 87.2% 90.8% Example 11 85.8% 85.1% 65.0% 1.3% 88.2% 92.0% Example 12 85.2% 84.6% 65.0% 1.4% 88.0% 91.8% Example 13 86.0% 84.8% 65.5% 1.2% 88.0% 92.0% Comparative Example 1 85.7% 84.8% 65.5% 1.1% 87.9% 91.9% Comparative Example 2 85.0% 84.2% 65.0% 2.0% 87.1% 91.5% Comparative Example 3 85.5% 84.5% 65.2% 1.1% 88.0% 91.9% Comparative Example 4 85.3% 84.0% 65.0% 1.4% 87.2% 91.5% Comparative Example 5 65.5% 62.1% 64.1% 15.5% 75.2% 81.5% Comparative Example 6 66.1% 63.0% 64.5% 14.5% 74.8% 81.1% Comparative Example 7 64.1% 62.1% 61.0% 16.4% 75.4% 81.5% Comparative Example 8 64.5% 62.5% 61.5% 15.6% 75.8% 81.0% Comparative Example 9 69.5% 68.6% 61.6% 12.5% 77.8% 82.7% Comparative Example 10 68.1% 66.2% 61.4% 16.5% 80.1% 84.5% ​ 65.0% 62.3% 63.2% 15.6% 75.5% 81.0% ​ 67.5% 64.2% 65.1% 10.1% 77.8% 82.5% ​ 65.0% 62.2% 63.0% 15.6% 75.6% 81.1% ​ 67.7% 64.3% 64.9% 10.8% 77.5% 82.6%

[0082] From the comparison of the test results of Examples 1-13 and Comparative Examples 1-10 in Table 2, it can be seen that:

[0083] The introduction of additive A in the examples can effectively improve the room temperature and high temperature cycle performance of the battery, and is beneficial to improve the high temperature storage performance of the battery. The oxidation potential of the nitrile compound is as high as 6.7V. The addition of the nitrile compound as an electrolyte additive can effectively reduce the oxidation of the electrolyte at high voltage, and effectively improve the cycle performance of the battery at high voltage. And the cyan group (-CN) of the nitrile compound can effectively complex with Co ions, effectively reducing the side reaction caused by the electrolyte. The four ether nitrile compound can transmit Li+ by using the ether bond contained in its own structure, and the discharge performance is obviously superior to that of the aliphatic nitrile compound, which can reduce the risk of deterioration of low temperature performance caused by nitrile structure.

[0084] The introduction of additive B can effectively improve the room temperature and high temperature cycle performance of the battery, and is beneficial to improve the high temperature storage performance of the battery. The isocyanate compound can form a film on the surface of the positive and negative electrodes, and the polymer SEI formed thereby can effectively protect the positive and negative active materials, maintain high stability during the cycle process, and reduce the SEI rupture caused by the volume change and Li + deintercalation. At the same time, the -NCO group of isocyanate can react with H2O and HF in the electrolyte, reducing the lithium salt decomposition and positive transition metal ion dissolution caused by the two, and inhibiting the corrosion of HF to the negative silicon material, thereby prolonging the cycle life of the battery.

[0085] From Examples 1-13 and Comparative Examples 1-10, it can be seen that additives A and B are only suitable for negative electrode systems with a silicon content of 10-30%. When the silicon content is less than 10%, there is no obvious difference between the negative electrode system and the ordinary graphite system, and the additive combination cannot be distinguished from the comparative group, and has no obvious effect. When the silicon content is higher than 30%, the volume change during the charging and discharging process of the silicon negative electrode is too large, and the SEI stability is seriously deteriorated, and the additive combination also cannot improve the SEI stability. Therefore, the additive combination is only suitable for negative electrode systems with a silicon content of 10-30%.

[0086] The specific embodiments described herein are merely illustrative of the present technology. Modifications or supplements to the specific embodiments described or similar ways of substitution can be made by those skilled in the art without departing from the technology of the present application or exceeding the scope defined by the appended claims.

Claims

1. A lithium-ion battery, comprising a positive electrode, a negative electrode, and an electrolyte, characterized in that, The negative electrode active material includes silicon negative electrode material, and the content of silicon negative electrode material is 10-30 wt% of the total weight of the negative electrode active material. The electrolyte includes a lithium salt, an organic solvent, and a first additive, wherein the first additive includes additive A having a structure of formula I and additive B having a structure of formula II. (I) (II) R1 to R6 are each independently selected from substituted or unsubstituted C1 to C10 alkylene or mesenchymal groups; The content of additive A is 0.05-5 wt% of the total electrolyte, and the content of additive B is 0.03-8 wt% of the total electrolyte.

2. The lithium-ion battery according to claim 1, characterized in that, The organic solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and propyl propionate (PP).

3. The lithium-ion battery according to claim 1, characterized in that, The content of additive A is 0.1 to 3 wt% of the total electrolyte, and the content of additive B is 0.1 to 5 wt% of the total electrolyte.

4. The lithium-ion battery according to claim 1, characterized in that, The additive A has the structure shown in formula (Ⅲ): (Ⅲ)。 5. The lithium-ion battery according to claim 1, characterized in that, The additive B is at least one of the structures shown in formula (Ⅳ) and formula (Ⅴ): (Ⅳ) (Ⅴ)。 6. The lithium-ion battery according to claim 1, characterized in that, The lithium salt is selected from one or more of lithium hexafluorophosphate (LiPF6), lithium difluorophosphate (LiDFP), lithium difluorobis(oxalate) phosphate (LiODFP), lithium tetrafluorooxalate phosphate (LiOTFP), lithium bis(oxalate) borate (LiBOB), lithium difluorobis(oxalate) borate (LiODFB), lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium bis(fluorosulfonyl)imide (LiFSI).

7. The lithium-ion battery according to claim 1, characterized in that, The lithium salt content accounts for 0.1 to 25.0 wt% of the total electrolyte.

8. The lithium-ion battery according to claim 1, characterized in that, It also includes a second additive, which comprises one or more of 1,3,6-hexanetrionitrile (HTCN), adiponitrile (ADN), 1,3-propanesulfonate lactone (PS), vinyl sulfate (DTD), fluorovinyl carbonate (FEC), tris(trimethylsilane)borate (TMSB), and tris(trimethylsilane)phosphate (TMSP).

9. The lithium-ion battery according to claim 8, characterized in that, The second additive accounts for 0.1 to 20 wt% of the total mass of the electrolyte.

10. An electrical device, characterized in that, Including the lithium-ion battery according to any one of claims 1-9.

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