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CN-122025824-A - Electrolyte, secondary battery, and electricity-using device

CN122025824ACN 122025824 ACN122025824 ACN 122025824ACN-122025824-A

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to electrolyte, a secondary battery and an electric device. The electrolyte comprises lithium salt and a solvent, wherein the solvent comprises carboxylic ester compounds and fluoro-sulfonamide compounds, and the structural formula of the fluoro-sulfonamide compounds is as follows: Wherein R1 and R2 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group. The electrolyte provided by the invention has excellent wide-temperature-range performance, so that the lithium ion battery can stably operate in a temperature range of-40 ℃ to 80 ℃ and has both low-temperature discharge performance and high-temperature cycle performance.

Inventors

  • YAO YUAN
  • QIN BINGSHENG
  • SHENG JIE

Assignees

  • 蜂巢能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260113

Claims (10)

  1. 1. The electrolyte is characterized by comprising lithium salt and a solvent, wherein the solvent comprises carboxylic ester compounds and fluoro-sulfonamide compounds; The structural formula of the fluoro sulfonamide compound is as follows: ; Wherein R1 and R2 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group.
  2. 2. The electrolyte of claim 1 wherein at least one of the substituted alkyl, substituted silyl or substituted aryl groups has a substituent selected from the group consisting of halogen and cyano.
  3. 3. The electrolyte according to claim 1, wherein the fluorosulfonamide compound includes at least one of (I-1) to (I-4): (I-1); (I-2); (I-3); (I-4)。
  4. 4. the electrolyte of claim 1, wherein the carboxylic acid ester compound comprises at least one of an acetate compound, a propionate compound, or a butyrate compound.
  5. 5. The electrolyte according to claim 4, wherein at least one of the characteristics (1) to (3) is satisfied: (1) The acetate compound comprises at least one of ethyl acetate, ethyl difluoroacetate and ethyl trifluoroacetate; (2) The propionate compound comprises at least one of methyl propionate, ethyl propionate, propyl propionate, butyl propionate, difluoro methyl propionate, trifluoro methyl propionate, difluoro ethyl propionate, trifluoro ethyl propionate, pentafluoroethyl propionate, difluoro propyl propionate and trifluoro propyl propionate; (3) The butyrate compounds comprise at least one of methyl butyrate, ethyl butyrate, propyl butyrate, methyl difluorobutyrate, methyl trifluorobutyrate, ethyl difluorobutyrate and ethyl trifluorobutyrate.
  6. 6. The electrolyte according to any one of claims 1 to 5, wherein at least one of the features (1) to (4) is satisfied: (1) The solvent accounts for 40% -75% of the total mass of the electrolyte; (2) The mass ratio of the carboxylic ester compound to the fluoro sulfonamide compound is 1 (0.05-1.5); (3) The lithium salt comprises at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium difluorosulfimide, lithium bis (trifluoromethylsulfonyl) imide, lithium dioxalate borate, lithium difluorooxalate borate, lithium difluorophosphate and lithium difluorodioxalate phosphate; (4) The concentration of the lithium salt in the electrolyte is 0.5 mol/L-2 mol/L.
  7. 7. The electrolyte of claim 6, further comprising a diluent and an additive; the diluent comprises at least one of fluoroether, fluorobenzene or halogenated alkane; The additive comprises at least one of sulfite compounds, sulfonate compounds, carbonate compounds or sulfate compounds.
  8. 8. The electrolyte according to claim 7, wherein at least one of the characteristics (1) to (9) is satisfied: (1) The fluoroether comprises 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether 1, 2-tetrafluoroethyl-2, 2-trifluoroethyl ether at least one of bis (2, 2-trifluoroethyl) ether or 1h,5 h-octafluoropentyl-1, 2-tetrafluoroethyl ether; (2) The fluorobenzene comprises at least one of fluorobenzene and 1, 2-difluorobenzene; (3) The halogenated alkane comprises at least one of dichloromethane, difluoromethane, chlorodifluoromethane, dichlorodifluoromethane, trichloromethane, dichloroethane, dichloropropane or dichlorobutane; (4) The diluent accounts for 25% -60% of the total mass of the electrolyte; (5) The sulfite compound comprises at least one of ethylene sulfite and propylene sulfite; (6) The sulfonate compound comprises at least one of 1, 3-propane sultone, 1, 4-butane sultone and 1, 3-propylene sultone; (7) The carbonate compound comprises at least one of vinylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate and diphenyl carbonate; (8) The sulfate compound comprises vinyl sulfate; (9) The additive accounts for 0.2% -10% of the total mass of the electrolyte.
  9. 9. A secondary battery is characterized by comprising a positive electrode plate, a negative electrode plate and the electrolyte according to any one of claims 1-8; and/or the positive electrode plate comprises a positive electrode active material, wherein the positive electrode active material comprises at least one of lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum acid, lithium-rich manganese-based material, lithium cobaltate or lithium manganate; And/or the negative electrode tab comprises a negative electrode active material comprising at least one of graphite, soft carbon, hard carbon, silicon, or lithium metal.
  10. 10. An electric device, characterized by comprising the electrolyte according to any one of claims 1 to 8; And/or the secondary battery according to claim 9.

Description

Electrolyte, secondary battery, and electricity-using device Technical Field The application relates to the technical field of lithium ion batteries, in particular to electrolyte, a secondary battery and an electric device. Background At present, lithium ion batteries are one of the most commonly used power/energy storage battery systems, but at extreme temperatures, the performance of electrolyte is greatly affected, and thus the cycle performance of the batteries is easily affected. For example, lithium iron phosphate batteries have low ionic conductivity and high interfacial resistance at low temperatures, and electrolytes with increased viscosity, reduced conductivity, and increased desolvation energy at low temperatures prevent lithium ions from intercalating into graphite negative electrodes. And the electrolyte mainly containing carbonate organic solvent is easy to generate side reaction at high temperature, so that partial components are decomposed, and the problems of gas production, byproduct accumulation and the like are caused. Therefore, how to obtain an electrolyte which can achieve both high and low temperature performance, so that the battery has excellent wide temperature range performance and has important significance. Disclosure of Invention In view of the above, the present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the invention provides the electrolyte, the secondary battery and the power utilization device, and the carboxylate compound and the fluoro-sulfonamide compound are mutually cooperated and matched, so that the electrolyte has excellent wide-temperature-range performance, the lithium ion battery can stably operate in a temperature range of-40 ℃ to 80 ℃, and the low-temperature discharge performance and the high-temperature cycle performance are both considered. In order to solve the technical problems, the invention is realized as follows: According to one aspect of the present invention, there is provided an electrolyte comprising a lithium salt and a solvent, the solvent comprising a carboxylic acid ester compound and a fluorosulfonamide compound; The structural formula of the fluoro sulfonamide compound is as follows: ; Wherein R1 and R2 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group. In some embodiments thereof, the substituent of at least one of the substituted alkyl, the substituted silyl, or the substituted aryl is selected from halogen or cyano. In some embodiments, the fluorosulfonamide-based compound includes at least one of (I-1) - (I-4): (I-1);(I-2); (I-3);(I-4)。 In some embodiments, the carboxylic acid ester compound comprises at least one of an acetate compound, a propionate compound, or a butyrate compound. In some embodiments, the acetate compound comprises at least one of ethyl acetate, ethyl difluoroacetate, ethyl trifluoroacetate. In some embodiments, the propionate compound includes at least one of methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl difluoropropionate, methyl trifluoropropionate, ethyl difluoropropionate, ethyl trifluoropropionate, ethyl pentafluoropropionate, propyl difluoropropionate, propyl trifluoropropionate. In some embodiments, the butyrate compounds include at least one of methyl butyrate, ethyl butyrate, propyl butyrate, methyl difluorobutyrate, methyl trifluorobutyrate, ethyl difluorobutyrate, ethyl trifluorobutyrate. In some embodiments, the solvent accounts for 40% -75% of the total mass of the electrolyte. In some embodiments, the mass ratio of the carboxylic ester compound to the fluoro-sulfonamide compound is 1 (0.05-1.5). In some embodiments, the lithium salt comprises at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (trifluoromethylsulfonyl) imide, lithium dioxalate borate, lithium difluorooxalato borate, lithium difluorophosphate, lithium difluorodioxalate phosphate. In some embodiments, the concentration of the lithium salt in the electrolyte is 0.5mol/L to 2mol/L. In some embodiments thereof, the composition further comprises a diluent and an additive, wherein the diluent comprises at least one of a fluoroether, a fluorobenzene, or a haloalkane; The additive comprises at least one of sulfite compounds, sulfonate compounds, carbonate compounds or sulfate compounds. In some of these embodiments, the process may include, the fluoroether comprises 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether 1, 2-tetrafluoroethyl-2, 2-trifluoroethyl ether at least one of bis (2, 2-trifluoroethyl) ether or 1H, 5H-octafluoropentyl-1, 2-tetrafluoroethyl ether. In some embodiments, the fluorobenzene comprises at least one of fluorobenzene, 1, 2-difluorobenzene. In some embodiments thereof, t