NONAQUEOUS ELECTROLYTE COMPOSITIONS

摘要

Electrolyte compositions comprising fluorinated acyclic carboxylic acid esters, fluorinated acyclic carbonates, and/or fluorinated acyclic ethers; co-solvents; and certain film-forming chemical compounds are described. The electrolyte compositions are useful in electrochemical cells, such as lithium ion batteries where they provide the improved performance of a combination of high capacity and high cycle life.

主权项

1. An electrolyte composition comprising:
a) at least one fluorinated solvent selected from the group consisting of:
(i) a fluorinated acyclic carboxylic acid ester represented by the formula:
R1—COO—R2,(ii) a fluorinated acyclic carbonate represented by the formula:
R3—OCOO—R4, and(iii) a fluorinated acyclic ether represented by the formula:
R5—O—R6,wherein R1, R2, R3, R4, R5, and R6, independently represent a linear or branched alkyl group; the sum of carbon atoms in any of R1 and R2, R3 and R4, and R5 and R6 is 2 to 7; at least two hydrogens in R1 and/or R2, R3 and/or R4, and R5 and/or R6 are replaced by fluorines; and neither R1, R2, R3, R4, R5, nor R6 contains a FCH2 or FCH group; b) at least one co-solvent selected from the group consisting of ethylene carbonate, fluoroethylene carbonate, and propylene carbonate; c) at least one cyclic carboxylic acid anhydride selected from the group consisting of where R7 to R14 are independently H, F, C1 to C10 linear or branched alkyl optionally substituted with one or more of fluorine, alkoxy, or thioalkyl, C2 to C10 alkene, or C6 to C10 aryl; and d) at least one electrolyte salt.