Effects of crown ethers on the electrochemical properties of polymeric solid electrolytes consisting of poly(ethylene oxide)-grafted poly(methylmethacrylates)

Abstract

Complexes of poly(ethylene oxide)-grafted poly(methylmethacrylate) (PEO-PMMA) and lithium (Li) salts have been prepared as polymeric solid electrolytes for rechargeable Li batteries. As high conductivities as 10 −3 S cm −1 at room temperature were obtained for the PEO-PMMA-based electrolytes containing Li salts with a liquid plasticizer. Effects of the crown ethers in the electrolytes were examined on the ionic conductance behavior. The addition of 12-crown-4 ( 12Cr4) or 15-crown-5 ( 15Cr5) improved the ionic conductivity to a small extent. However, the ionic mobility of Li + in the electrolyte was improved by the addition of 15Cr5. The transport number of Li + in the electrolytes containing 15Cr5 was much higher than those in the electrolytes without crown ethers. The specific solvation of Li +-15Cr5 contributes not only to the improvement in the ionic mobility of Li + but also to the suppression in the reaction rate of the Li electrode in the polymeric electrolytes.