ELECTROLYTE COMPOSITION WITH FLUORINATED ACYCLIC ESTER AND FLUORINATED CYCLIC CARBONATE
An electrochemical cell comprises an anode, a cathode and an electrolyte composition, wherein the anode comprises as anode active material a combination of at least a carbon material and a silicon material; and the electrolyte composition comprises a solvent, from 0.5 wt. % to 70 wt. %, based on the total weight of the electrolyte, of a fluorinated acyclic carboxylic acid ester compound, from 0.5 wt. % 10 wt. %, based on the total weight of the electrolyte, of a fluorinated cyclic carbonate compound; and an electrolyte salt.
1 . An electrochemical cell comprising an anode, a cathode and an electrolyte composition, wherein said anode comprises as an anode active material a combination of at least a carbon material and a silicon material; and said electrolyte composition comprises:
a solvent;
from 0.5 wt. % to 70 wt. %, based on the total weight of the electrolyte, of a fluorinated acyclic carboxylic acid ester compound of general formula
R1-COO—R2
wherein R1 is a C1-C4 alkyl group, and R2 is C1-C4 fluoroalkyl group,
from 0.5 wt. % to 10 wt. %, based on the total weight of the electrolyte, of a fluorinated cyclic carbonate compound; and
an electrolyte salt.
2 . The electrochemical cell according to claim 1 , wherein the anode is a composite material selected from Si/C, SiOa/C and Si/SiOa/C, with 0<a<2.
3 . The electrochemical cell according to claim 1 , wherein said fluorinated acyclic carboxylic acid ester is selected from the group consisting of 2,2-difluoroethyl acetate, 2,2,2-trifluoroethyl acetate, 2,2-difluoroethyl propionate, 3,3-difluoropropyl acetate, 3,3-difluoropropyl propionate, and mixtures thereof.
4 . The electrochemical cell according to claim 3 , wherein said fluorinated acyclic carboxylic acid ester is 2,2-difluoroethyl acetate.
5 . The electrochemical cell according to claim 3 , wherein said fluorinated acyclic carboxylic acid ester is 2,2-difluoroethyl propionate.
6 . The electrochemical cell according to claim 4 , wherein said fluorinated acyclic carboxylic acid ester is 2,2,2-trifluoroethyl acetate.
7 . The electrochemical cell according to claim 1 , wherein the content of the fluorinated acyclic carboxylic acid ester compound is from 0.5 wt. % to 10 wt. %, based on the total weight of the electrolyte.
8 . The electrochemical cell according to claim 1 , wherein said fluorinated cyclic carbonate is selected from the group consisting of 4-fluoroethylene carbonate, 4,5-difluoro-1,3-dioxolan-2-one, 4,5-difluoro-4-methyl-1,3-dioxolan-2-one, 4,5-difluoro-4,5-dimethyl-1,3-dioxolan-2-one, 4,4-difluoro-1,3-dioxolan-2-one, 4,4,5-trifluoro-1,3-dioxolan-2-one, tetrafluoroethylene carbonate, and mixtures thereof.
9 . The electrochemical cell according to claim 1 , wherein the content of the fluorinated cyclic carbonate compound is from 1 wt. % to 9 wt. %.
10 . The electrochemical cell according to claim 1 , wherein the solvent of the electrolyte composition comprises a non-fluorinated cyclic carbonate.
11 . The electrochemical cell according to claim 1 , wherein the solvent of the electrolyte composition comprises a non-fluorinated acyclic carbonate.
12 . The electrochemical cell according to claim 1 , wherein the electrolyte composition further comprises an additive selected from a lithium boron compound, a cyclic sultone, a cyclic sulfate, a cyclic carboxylic acid anhydride, or a combination thereof.
13 . An electronic device, transportation device, or telecommunications device, comprising an electrochemical cell according to claim 1 .
14 . A method of improving cycling performance at high temperature of an electrochemical cell comprising an anode and an electrolyte composition, wherein said anode comprises, as an anode active material, a combination of at least a carbon material and a silicon material, the method comprising:
adding an additive to the electrolyte composition, the additive comprising:
from 0.5 wt. % to 70 wt. %, based on the total weight of the electrolyte, of a fluorinated acyclic carboxylic acid ester compound of general formula
R 1 —COO—R 2
wherein R 1 is a C1-C4 alkyl group, and R 2 is C1-C4 fluoroalkyl group, and
from 0.5 wt. % to 10 wt. %, based on the total weight of the electrolyte, of a fluorinated cyclic carbonate compound.
15 . The electrochemical cell according to claim 10 , wherein the non-fluorinated cyclic carbonate is selected from the group consisting of ethylene carbonate, propylene carbonate, and mixtures thereof.
16 . The electrochemical cell according to claim 11 , wherein the non-fluorinated acyclic carbonate is selected from the group consisting of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate; and mixtures thereof.
17 . The electrochemical cell according to claim 6 , wherein the content of the fluorinated acyclic carboxylic acid ester compound is from 2 wt. % to 5 wt. %, based on the total weight of the electrolyte.
18 . The electrochemical cell according to claim 8 , wherein said fluorinated cyclic carbonate is selected from the group consisting of 4-fluoroethylene carbonate, 4,5-difluoro-1,3-dioxolan-2-one, and mixtures thereof.
19 . The electrochemical cell according to claim 9 , wherein the content of the fluorinated cyclic carbonate compound is from 2 wt. % to 5 wt. %.