Electrolyte solution, and secondary battery, battery module, battery pack and electrical apparatus thereof
View Patent ↗Provided are an electrolyte solution, comprising an organic solvent, an electrolyte lithium salt, and an additive; wherein the organic solvent comprises a fluorinated solvent; the electrolyte lithium salt comprises a fluorine-containing sulfonylimide lithium salt; and the additive comprises a lithium halide salt. The electrolyte solution of the present application has good conductivity and flame retardancy, and a lithium-ion battery comprising the electrolyte solution has at least one of improved energy density, safety performance, output performance, and cycling performance.
1. An electrolyte solution, comprising an organic solvent containing a fluorinated solvent, an electrolyte lithium salt, and an additive;
wherein
the organic solvent containing a fluorinated solvent is one selected from:
(i) a combination of at least two selected from fluoroethylene carbonate (FEC), fluoroethyl methylcarbonate (FEMC), 3-(2,2,3,3-tetrafluoropropoxy)-1,2-propylene oxide, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, and nonafluoroisobutyl methyl ether,
(ii) a combination of at least two selected from fluoroethylene carbonate (FEC), 3-(2,2,3,3-tetrafluoropropoxy)-1,2-propylene oxide, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and nonafluoroisobutyl methyl ether,
(iii) fluoroethyl methylcarbonate (FEMC),
(iv) fluoroethylene carbonate (FEC),
(v) a hydrofluoroether(s) (HFE) selected from at least one of 3-(2,2,3,3-Tetrafluoropropoxy)-1,2-propylene oxide, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, methylnonafluorobutyl ether, ethyl nonafluorobutyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and nonafluoroisobutyl methyl ether, or
(vi) a combination of ethyl methyl carbonate (EMC) and a hydrofluoroether(s) (HFE) selected from at least one of fluoroethylene carbonate (FEC), Fluoroethyl methyl carbonate (FEMC), 3-(2,2,3,3-tetrafluoropropoxy)-1,2-propylene oxide, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, and nonafluoroisobutyl methyl ether;
the electrolyte lithium salt comprises a fluorine-containing sulfonylimide lithium salt;
the additive comprises a lithium halide salt;
the fluorine-containing sulfonylimide lithium salt, lithium halide salt, and fluorinated solvent satisfy: t= [(k*a*c)/(k*a+c)]/b, and tis from 0.0004 to 0.1000,
k is a molar concentration of the electrolyte lithium salt in the electrolyte solution, a unit of the molar concentration is mol/L,
a is a molar percent of the fluorine-containing sulfonylimide lithium salt relative to a total molar amount of the electrolyte lithium salt,
b is a weight percentage of the fluorinated solvent relative to a total weight of the organic solvent,
c is a weight percentage of the lithium halide salt relative to a total weight of the electrolyte, and
a, b, c, and k each are not 0.
2. The electrolyte solution according to claim 1 , wherein based on a total weight of the organic solvent, a content of the fluorinated solvent is 20% by weight or more.
3. The electrolyte solution according to claim 1 , wherein a molar concentration of the electrolyte lithium salt is 0.5 mol/L to 8 mol/L.
4. The electrolyte solution according to claim 1 , wherein based on a total weight of the electrolyte solution, a content of the lithium halide salt is 0.05% by weight to 10% by weight.
5. The electrolyte solution according to claim 1 , wherein based on a total molar weight of the electrolyte lithium salt, a molar percentage of the fluorine-containing sulfonylimide lithium salt is at least 30%.
6. The electrolyte solution according to claim 1 , wherein the lithium halide salt is selected from at least one of lithium iodide, lithium bromide, lithium chloride, and lithium fluoride.
7. The electrolyte solution according to claim 1 , wherein the fluorine-containing sulfonylimide lithium salt is selected from at least one of lithium bis(fluorosulfonyl) imide, lithium bis(trifluoromethanesulfonyl) imide, lithium bis(pentafluoroethanesulfonyl) imide and lithium bis(perfluoro-1-butanesulfonyl) imide.
8. The electrolyte solution according to claim 1 , wherein the electrolyte lithium salt further includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, and lithium perchlorate.
9. The electrolyte solution according to claim 1 , further comprising at least one of a film-forming additive, a flame retardant additive, an anti-overcharge additive, and a conductive additive.
10. A lithium ion secondary battery, comprising the electrolyte solution of claim 1 .
11. A battery module comprising a secondary battery according to claim 10 .
12. A battery pack comprising the battery module according to claim 11 .
13. A power consumption device, comprising the secondary battery according to claim 10 .