Physical and Electrochemical Properties of Fluorinated Dialkyl Ethers

Abstract

Dialkyl ethers show high relative permittivities and low viscosities as compared to the corresponding linear carbonates. We have synthesized 1-(2-fluoroethoxy)-2-(2,2,2-trifluoroethoxy)ethane (FETFEE). The relative permittivity and viscosity of FETFEE were higher than those of 1,2-diethoxyethane (DEE, ethylene glycol diethyl ether). The conductivity of 1 mol dm⁻³ LiPF₆ solution in FETFEE was higher than that in 1-ethoxy-2-(2,2,2-trifluoroethoxy)ethane (ETFEE). The use of FETFEE as a co-solvent improved the discharge capacity of a Li | LiCoO₂ coin cell.