A NON-AQUEOUS ELECTROLYTE SYSTEM FOR USE IN BATTERIES, CAPACITORS OR ELECTROCHROMIC DEVICES AND A METHOD FOR THE PREPARATION THEREOF

摘要

A new non-aqueous electrolyte system for use in batteries, capacitors or electrochromic displays, and consisting essentially of an alkali or ammonium salt, a solvent mixture, and optionally a polymer is disclosesd. The new electrolyte system is characterised in that the solvent mixture comprises a mixture of ethylene carbonate (EC) and gamma -valerolactone ( gamma -VL), optionally containing one or more additional solvents selected from other organic carbonates, other lactones, esters and glymes, said system optionnaly being confined in a separator. The electrolyte system can be applied in a broad voltage range, has a conductivity higher than 10<-3> S/cm at room temperature, and shows a high stability against reduction. The improved stability towards reduction is mirrored in a cycling efficiency which is superior to the cycling efficiency of known non-aqueous electrolyte systems.