Electrolyte, battery, battery pack and electric equipment

Abstract

The invention provides an electrolyte, a battery, a battery pack and electric equipment, the electrolyte comprises a first additive and a second additive, the first additive comprises a compound shown as a formula 1, in the formula 1, R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently H, F, C1-C20 alkyl, C1-C20 fluoroalkyl and C1-C20 fluoroalkenyl, and at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 contains F; the second additive comprises at least one of R-NI, alkali metal salt of iodine and alkaline earth metal salt of iodine, and R is C1-C20 alkyl. The electrolyte provided by the invention can effectively restrain the problem of lithium precipitation of the battery cell in the circulation process, and can relieve the self-discharge behavior of the battery cell at the same time.

Description

Technical Field

[0001] This invention relates to the field of batteries, and more particularly to an electrolyte, a battery, a battery pack, and an electrical device. Background Technology

[0002] In recent years, with the rapid development of portable electronic products and new energy vehicles, higher requirements have been placed on the performance of lithium-ion batteries, among which the lifespan of the battery cells is particularly important.

[0003] During long-term cycling, the dissolution of transition metals, the consumption of electrolyte, and lithium plating will accelerate the consumption of active lithium, thereby reducing the cycle life of the battery cell. In particular, the lithium plating problem has been a major challenge that has plagued battery cell development for decades.

[0004] Using electrolyte additives to suppress the formation of lithium dendrites is one of the main measures to delay lithium plating in battery cells. However, while existing electrolyte additives have a certain effect on suppressing the formation of dead lithium, they also introduce the problem of increased self-discharge of the battery cells. Self-discharge of the battery cells will cause the battery capacity to gradually decrease, affecting the battery's energy storage efficiency, thereby accelerating battery aging and shortening the battery's lifespan. Summary of the Invention

[0005] This invention provides an electrolyte that can effectively suppress lithium plating in battery cells during cycling and also alleviate the self-discharge behavior of battery cells.

[0006] The present invention also provides a battery that, because it includes the above-mentioned electrolyte, has the advantages of long cycle life and high energy storage efficiency.

[0007] The present invention also provides a battery pack including the above-mentioned battery, which has the advantages of high energy storage efficiency and long service life.

[0008] The present invention also provides an electrical device that, because it includes the aforementioned battery or battery pack, has good electrical performance and a long service life.

[0009] In a first aspect, the present invention provides an electrolyte comprising a first additive and a second additive, wherein the first additive comprises a compound shown in Formula 1.

[0010] Formula 1,

[0011] In Equation 1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independent of H, F, and C1-C. 20 Alkyl, C1-C 20 Fluoroalkyl, C1-C 20Fluoroalkenyl groups, and R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 At least one of them contains F;

[0012] The second additive includes at least one of R-NI, an alkali metal salt of iodine, and an alkaline earth metal salt of iodine, wherein R is C1-C. 20 Alkyl groups.

[0013] Optionally, in Equation 1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independently selected from H, F, C1-C 10 Alkyl, C1-C 10 Fluoroalkyl, C1-C 10 Fluoroalkenyl groups, and R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 At least one of them contains F.

[0014] Optionally, the first additive is pentafluoroquinone and / or decafluoroquinone.

[0015] Optionally, the first additive has a mass percentage content of 0.1wt%-5wt% in the electrolyte;

[0016] And / or, the second additive has a mass percentage content of 0.1wt%-2wt% in the electrolyte.

[0017] Optionally, the molar ratio of the first additive to the second additive is 1-3:1.

[0018] Optionally, the product also includes a third additive, which comprises at least one of vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate, tris(trimethylsilane) phosphate, triallyl phosphate, triargyl phosphate, trimethyl phosphate, triethyl phosphate, hexamethylene diisocyanate, and methylene disulfonate.

[0019] Optionally, the electrolyte further includes an organic solvent, which includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butenyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0020] Optionally, the electrolyte further includes a lithium salt, which includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium difluorooxalate borate, lithium difluorodioxalate phosphate, lithium tetrafluorooxalate phosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium perfluorobutyl sulfonate, and lithium fluorinated fatty acids.

[0021] In a second aspect, the present invention provides a battery comprising a positive electrode, a negative electrode, and the electrolyte described in the first aspect.

[0022] Thirdly, the present invention provides a battery pack comprising the battery described in the second aspect.

[0023] Fourthly, the present invention provides an electrical device comprising the battery described in the second aspect or the battery pack described in the third aspect.

[0024] The electrolyte provided by this invention comprises a first additive and a second additive. The second additive can undergo a redox reaction with lithium metal on the negative electrode surface, reactivating the dead metal into lithium ions, thereby inhibiting lithium plating in the battery cell. The iodine in the first additive and the second additive have a strong interaction, which can delay the shuttle of iodide ions in the electrolyte, thereby reducing the self-discharge of the battery cell. At the same time, the first additive can also undergo a reduction reaction on the negative electrode surface to generate a LiF-rich SEI film, thereby further reducing the risk of lithium plating in the battery cell. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0026] Figure 1 The graph shows a comparison of the self-discharge data of the batteries using the electrolytes of Example 1 and Comparative Example 2.

[0027] Figure 2 The graph shows a comparison of the capacity retention rates of batteries using the electrolytes of Example 1 and Comparative Example 2 at room temperature. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In a first aspect, the present invention provides an electrolyte comprising a first additive and a second additive, wherein the first additive comprises a compound with the structure shown in Formula 1.

[0030] Formula 1,

[0031] In Equation 1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independent of H, F, and C1-C. 20 Alkyl, C1-C 20 Fluoroalkyl, C1-C 20 Fluoroalkenyl groups, and R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 At least one of them contains F;

[0032] The second additive includes at least one of R-NI, an alkali metal salt of iodine, and an alkaline earth metal salt of iodine, wherein R is C1-C. 20 Alkyl groups.

[0033] The electrolyte provided by this invention, containing a first additive and a second additive, can not only effectively alleviate lithium plating in the battery cell but also mitigate its self-discharge behavior. Specifically: the addition of the second additive can undergo a redox reaction with lithium metal on the negative electrode surface, reactivating the dead metal into lithium ions, thereby inhibiting lithium plating; the addition of the first additive can strongly interact with iodide ions and / or elemental iodine in the second additive, anchoring iodide ions and / or elemental iodine, thereby delaying the shuttle movement of iodide ions in the electrolyte and reducing the self-discharge of the battery cell. At the same time, the first additive can also undergo a reduction reaction on the negative electrode surface to generate a LiF-rich SEI film, thereby further reducing the risk of lithium plating in the battery cell.

[0034] For example, the alkali metal salts of iodine mentioned above can be lithium iodide, sodium iodide, potassium iodide, rubidium iodide, and cesium iodide, etc.; the alkaline earth metal salts of iodine can be beryllium iodide, magnesium iodide, calcium iodide, strontium iodide, and barium iodide, etc.; R-NI can be CH3CH2CH2CH2CH2CH2CH2CH2NI, CH3CH2CH2CH2CH2CH2NI, CH3CH2CH2CH2CH2NI, CH3CH2CH2CH2CH2NI, CH3CH2CH2CH2NI, CH3CH2CH2CH2NI, CH3CH2CH2CH2NI, CH3NI, etc.

[0035] It is understood that R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 At least one of the F-containing molecules in the formula is derived from F and / or C1-C. 20 Fluorinated alkyl groups and / or C1-C 20 Fluoroalkenyl groups.

[0036] In one specific embodiment, in formula 1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independently selected from H, F, C1-C 10 Alkyl, C1-C 10 Fluoroalkyl, C1-C 10 Fluoroalkenyl groups, and R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 At least one of them contains F.

[0037] In one specific embodiment, the first additive is pentafluoroquinone and / or decafluoroquinone.

[0038] In one specific embodiment, the first additive has a mass percentage content of 0.1wt%-5wt% in the electrolyte;

[0039] And / or, the second additive has a mass percentage content of 0.1wt%-2wt% in the electrolyte.

[0040] Among them, the first additive within the above mass percentage range has a significant effect on reducing cell self-discharge, reducing cell lithium plating, and improving cell cycle performance. If the mass percentage of the first additive is higher than 5.0 wt%, the cell cost increases and too much LiF component is generated, which has a negative effect on the battery impedance and the maintenance of charge and discharge efficiency. If it is lower than 0.1 wt%, the SEI film cannot effectively coat the negative electrode material, and the effect on improving battery performance is limited.

[0041] The second additive within the above-mentioned mass percentage range can achieve a good balance between reducing cell lithium plating and cell self-discharge. If the content of the second additive is too low, although it ensures that the cell self-discharge does not increase excessively, it cannot reactivate most dead cells into lithium ions, thus failing to suppress cell lithium plating effectively. If the content of the second additive is too high, the cell self-discharge increases, leading to a gradual reduction in battery capacity, affecting the battery's energy storage efficiency, and thus accelerating battery aging.

[0042] For example, the first additive in the electrolyte has a mass percentage of 0.5 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2.0 wt%, 2.2 wt%, 2.5 wt%, 2.8 wt%, 3.0 wt%, 3.2 wt%, 3.5 wt%, 3.8 wt%, 4.0 wt%, 4.2 wt%, 4.5 wt%, 4.8 wt%, etc.; and the second additive in the electrolyte has a mass percentage of 0.2 wt%, 0.5 wt%, 0.7 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.7 wt%, 1.9 wt%, etc.

[0043] In one specific embodiment, the molar ratio of the first additive to the second additive is 1-3:1.

[0044] In this embodiment, by controlling the ratio of the two additives, the synergistic effect of the two additives can be better utilized, suppressing lithium plating in the cell while reducing the cell's self-discharge, thereby achieving better cycle and storage performance of the battery.

[0045] In one specific embodiment, the electrolyte further includes a third additive, which includes at least one of vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate, tris(trimethylsilane) phosphate, triallyl phosphate, triargyl phosphate, trimethyl phosphate, triethyl phosphate, hexamethylene diisocyanate, and methylene dimethyl sulfonate.

[0046] The third additive has a good affinity for the negative electrode surface, which can help the first additive to build a stable SEI film on the negative electrode surface, further protecting the negative electrode structure from solvent molecules, HF, and F in the electrolyte. - Corrosion from other impurities.

[0047] The amount of the third additive is not particularly limited in this invention. Generally speaking, the mass ratio of the third additive to the electrolyte does not exceed 2 wt%.

[0048] In one specific embodiment, the electrolyte further includes an organic solvent, which includes at least one of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butenyl carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0049] In one specific embodiment, the electrolyte further includes a lithium salt, which includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium difluorooxalate borate, lithium difluorodioxalate phosphate, lithium tetrafluorooxalate phosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium perfluorobutyl sulfonate, and lithium fluorinated fatty acids.

[0050] The present invention does not specifically limit the mass percentage of the lithium salt in the electrolyte. Those skilled in the art can adjust it according to the actual situation. However, in order for the lithium salt to be dissolved in the organic solvent to form an electrolyte with high stability and good lithium conductivity, and at the same time to make the electrolyte viscosity appropriate, in some embodiments, the mass percentage of the lithium salt in the electrolyte is 6wt%-25wt%.

[0051] For example, the mass percentage of the non-aqueous organic solvent is 60wt%-92wt%, preferably 65wt%-85wt%. When the organic solvent is within the above range, the lithium salt can be fully dissolved in the electrolyte, which helps to prepare an electrolyte with high conductivity and strong stability, thus ensuring stable electrochemical performance of the battery.

[0052] In a second aspect, the present invention provides a battery comprising the electrolyte, positive electrode, and negative electrode as described in the first aspect above.

[0053] The aforementioned positive electrode includes positive electrode active materials, which include, but are not limited to, LiCoO2, LiMn2O4, LiMnO2, Li2MnO4, LiFePO4, and Li 1+a Mn 1-b M b O2, LiCo 1-b M b O2, LiFe 1-b M b PO4, Li2Mn 1-b O4, LiNi xCo y Mn z At least one of O2, M is selected from one or more of Ni, Co, Mn, Al, Cr, Mg, Zr, Mo, V, Ti, B, and F, 0≤a<0.2, 0≤b<1, and x+y+z=1.

[0054] Furthermore, positive electrode active materials include, but are not limited to, LiCoO2, LiFeMnPO4, and LiNi. 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, etc.

[0055] The aforementioned negative electrode sheet includes a negative electrode active material, which can be a conventional material in the art, including but not limited to one or more of carbonaceous materials, silicon-carbon materials, alloy materials, and lithium-containing metal composite oxides. Furthermore, the negative electrode active material can be one or more of graphite, soft carbon, hard carbon, silicon, silicon oxides, silicon-carbon composites, and lithium titanate.

[0056] The battery may also include a separator, and the material of the separator can be selected by technicians from conventional separators, such as polyolefin, aromatic polyamide, polytetrafluoroethylene, polyethersulfone, etc.

[0057] Thirdly, the present invention provides a battery pack comprising the battery described in the second aspect.

[0058] Fourthly, the present invention provides an electrical device comprising the battery described in the second aspect or the battery pack described in the third aspect.

[0059] It should be noted that the above-mentioned electrical equipment can be any equipment that conventionally requires electricity, such as, but not limited to, computers, electric vehicles, air conditioners, refrigerators, washing machines, microwave ovens, printers, fax machines, etc.

[0060] The present invention will be further described below with reference to specific embodiments:

[0061] Example 1

[0062] This example provides an electrolyte comprising: a first additive: decafluorobenzene (in Formula 1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R... 10 All are F); second additive: methylammonium hydroiodate (CH3NI); third additive: vinylene carbonate;

[0063] The electrolyte, by mass fraction, comprises: ethylene carbonate 30 wt%; dimethyl carbonate 22 wt%; diethyl carbonate 12 wt%; methyl ethyl carbonate 30 wt%; vinylene carbonate 2.1 wt%; methylammonium hydroiodate CH3NI 0.5 wt%; fluoroethylene carbonate 1.4 wt%; decafluorobenzene 2 wt%; and LiPF6 1 mol / L.

[0064] Its preparation method includes the following steps:

[0065] 1) Mix ethylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate solvent evenly at room temperature;

[0066] 2) Add vinylene carbonate, fluoroethylene carbonate, CH3NI and decafluorobenzene to the solution in step 1), and sonicate for 30 min;

[0067] 3) Add the lithium salt LiPF6 to the solution prepared in step 2) and sonicate until the lithium salt is completely dissolved in the solution.

[0068] Example 2

[0069] Basically the same as Example 1, except that the structure of the first additive is changed. The first additive is a compound with the structure shown in Formula 1, where R1 is trifluoromethyl, R2, R3, R4, R5, R6, R7, R8, R9, R 10 All are H.

[0070] Example 3

[0071] Basically the same as Example 1, except that the structure of the first additive is changed. The first additive is a compound with the structure shown in Formula 1, where R1, R3, R5, R7, and R9 are trifluoromethyl, and R2, R4, R6, R8, and R9 are trifluoromethyl, R2, R4, R6, R8, and R9 are trifluoromethyl, R2, R4, R6, R8, and R9 are trifluoromethyl, R2, R4, R6, R8, R9 ... 10 All are H.

[0072] Example 4

[0073] Basically the same as Example 1, except that the structure of the first additive is changed. The first additive is a compound with the structure shown in Formula 1, where R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 All are trifluoromethyl.

[0074] Example 5

[0075] It is basically the same as Example 1, except that the amount of the first additive is changed to 3wt%.

[0076] Example 6

[0077] It is basically the same as Example 1, except that the structure of the second additive is changed and the second additive is KI.

[0078] Example 7

[0079] It is basically the same as Example 1, except that the second additive is MgI.

[0080] Example 8

[0081] It is basically the same as Example 1, except that the second additive is tetra-tert-butylaminoiodine.

[0082] Example 9

[0083] The process is basically the same as in Example 1, except that the amounts of the first and second additives are changed. Specifically, the amount of decafluoroquinone is 0.5 wt% and the amount of methylammonium hydroiodide CH3NI is 0.1 wt%.

[0084] Example 10

[0085] The process is basically the same as in Example 1, except that the amounts of the first and second additives are changed. Specifically, the amounts of decafluoroquinone are 5 wt% and methylammonium hydroiodide CH3NI are 2 wt%.

[0086] Example 11

[0087] The process is basically the same as in Example 1, except that the amounts of the first and second additives are changed. Specifically, the amounts of decafluoroquinone are 5 wt% and methylammonium hydroiodide CH3NI are 1 wt%.

[0088] Example 12

[0089] It is basically the same as Example 1, except that the lithium salt is changed to LiPF6 and LiFSI with a mass ratio of 7:3.

[0090] Example 13

[0091] It is basically the same as Example 1, except that vinylene carbonate is replaced with methyl methane disulfonate.

[0092] Example 14

[0093] The process is basically the same as in Example 1, except that, by mass fraction, the electrolyte includes ethyl acetate 30 wt%; dimethyl carbonate 22 wt%; diethyl carbonate 12 wt%; methyl ethyl carbonate 30 wt%; vinylene carbonate 2.1 wt%; methylammonium hydroiodate CH3NI 0.5 wt%; fluoroethylene carbonate 1.4 wt%; decafluorobenzene 2 wt%; and LiPF6 1 mol / L.

[0094] Comparative Example 1

[0095] It is basically the same as Example 1, except that: no first additive and second additive are added.

[0096] Comparative Example 2

[0097] It is basically the same as Example 1, except that the first additive is not added.

[0098] Comparative Example 3

[0099] It is basically the same as Example 1, except that no second additive is added.

[0100] Experimental Example 1

[0101] This example provides a series of lithium-ion batteries, each including the electrolyte of the above embodiments or comparative examples.

[0102] 1. Cathode Preparation: LiFePO4 cathode material, conductive agent SuperP (conductive carbon black), conductive agent CNT (carbon nanotubes), and binder PVDF (polyvinylidene fluoride) are mixed evenly at a mass ratio of 96.3:2:0.5:1.2. The mixture is then vacuum-stirred until uniformly fluid. This slurry is then evenly coated (50 μm thick) onto both sides of an aluminum foil. The foil is subsequently dried at 85°C, cold-pressed, trimmed, cut into sheets, slit, and then... o After vacuum drying for 12 hours, the areal density obtained after welding the electrode tabs was 33 mg / cm³. 2 The positive electrode sheet.

[0103] 2. Negative Electrode Preparation: Graphite negative electrode material, conductive agent SuperP (conductive carbon black), binder SBR (polyvinylidene fluoride), and thickener CMC are mixed evenly at a mass ratio of 96.3:2:0.5:1.2. The mixture is then vacuum-stirred until uniformly fluid. This slurry is then evenly coated (45 μm thick) onto both sides of an aluminum foil. The foil is subsequently dried at 85°C, cold-pressed, edge-trimmed, cut into sheets, slit, and then... o After vacuum drying for 12 hours, the areal density obtained after welding the electrode tabs is 20 mg / cm³. 2 The negative electrode sheet.

[0104] 3. Separator: A PP diaphragm with a thickness of 14µm is selected.

[0105] 4. Cell preparation: The positive and negative electrode sheets are die-cut to prepare a stacked small soft-pack cell with 7 layers of positive electrode and 8 layers of negative electrode. 7g of the above electrolyte is injected into the aluminum-shell lithium battery cell by manual injection. The cell is then aged at 25°C dew point environment for 3 days, followed by formation. After formation, a second injection of 3g of experimental electrolyte is performed, followed by high-temperature immersion for 2 days. Finally, capacity testing is performed, and the cell is subjected to a 7-day self-discharge test.

[0106] Performance testing:

[0107] 1. The cells from the capacity-tested line in Example 1 were subjected to a cycle test to evaluate the room-temperature cycling performance of the cells equipped with the electrolyte described above. Table 1 records the capacity retention rate (SOH) of different embodiments after 500 cycles:

[0108] Experimental steps:

[0109] 1) Capacity calibration:

[0110] ① Charging: At room temperature (25±3℃), charge at a constant current and constant voltage of 0.5C to 3.8V, cut off at 0.02C, and let stand for 30 minutes;

[0111] ② Discharge: At room temperature (25±3℃), discharge at a constant current of 0.5C to 2.0V, and let stand for 30 minutes;

[0112] A total of 3 discharges were performed. The discharge capacity of the 3rd discharge was recorded as the battery's nominal discharge capacity C0.

[0113] 2) Let it sit for 10 hours to ensure the battery temperature is 25℃.

[0114] 3) 1C0 constant current and constant voltage charging to 3.8V.

[0115] 3) Let it sit for 30 minutes.

[0116] 4) Discharge to 2.0V with 1C0 constant current.

[0117] 5) Let it sit for 30 minutes.

[0118] 6) Cyclic steps 2)-5) 5000 times.

[0119] 2. Self-discharge test:

[0120] After capacity testing, the battery cell is placed at 25% SOC (State of Charge). The OCV (Optical Value) of the cell at this point is recorded as V0. The cell is then stored at 25°C for different periods of time. After 7 days, the OCV of the cell is tested and recorded as V. 7； Table 1 records V7-V0 and defines them as the K value of self-discharge.

[0121] Table 1

[0122]

[0123] As shown in Table 1, compared with the comparative example, the battery cell containing the electrolyte formulation of the present invention has a significantly reduced self-discharge voltage drop after 7 days; and the battery cell containing the electrolyte formulation of the embodiment has a significant advantage in room temperature cycling, specifically, after 500 cycles, the battery cell of Example 1 has a 3.8% higher capacity retention rate than the battery cell of Comparative Example 1.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrolyte, characterized in that, It includes a first additive and a second additive, wherein the first additive includes a compound shown in Formula 1. Formula 1, In Equation 1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independent of H, F, and C1-C. 20 Alkyl, C1-C 20 Fluoroalkyl, C1-C 20 Fluoroalkenyl groups, and R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 At least one of them contains F; The second additive includes at least one of R-NI, an alkali metal salt of iodine, and an alkaline earth metal salt of iodine, wherein R is C1-C. 20 Alkyl groups.

2. The electrolyte according to claim 1, characterized in that, In Equation 1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independently selected from H, F, C1-C 10 Alkyl, C1-C 10 Fluoroalkyl, C1-C 10 Fluoroalkenyl groups.

3. The electrolyte according to claim 2, characterized in that, The first additive is pentafluoroquinone and / or decafluoroquinone.

4. The electrolyte according to any one of claims 1-3, characterized in that, The first additive has a mass percentage content of 0.1wt%-5wt% in the electrolyte; And / or, the second additive has a mass percentage content of 0.1wt%-2wt% in the electrolyte.

5. The electrolyte according to any one of claims 1-4, characterized in that, The molar ratio of the first additive to the second additive is 1-3:

1.

6. The electrolyte according to any one of claims 1-5, characterized in that, It also includes a third additive, which includes at least one of vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate, tris(trimethylsilane) phosphate, triallyl phosphate, triargyl phosphate, trimethyl phosphate, triethyl phosphate, hexamethylene diisocyanate, and methylene disulfonate.

7. The electrolyte according to any one of claims 1-6, characterized in that, It also includes organic solvents, including at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butenyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

8. The electrolyte according to any one of claims 1-7, characterized in that, It also includes lithium salts, including at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium difluorooxalate borate, lithium difluorodioxalate phosphate, lithium tetrafluorooxalate phosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium perfluorobutyl sulfonate, and lithium fluorinated fatty acids.

9. A battery, characterized in that, It includes a positive electrode, a negative electrode, and the electrolyte according to any one of claims 1-8.

10. A battery pack, characterized in that, Includes the battery as described in claim 9.

11. An electrical appliance, characterized in that, Includes the battery of claim 9 or the battery pack of claim 10.

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