Polarization Behavior of Lithium Electrode in Solid Electrolytes Consisting of a Poly(Ethylene Oxide)‐Grafted Polymer

Abstract

A complex of poly(ethylene oxide)‐grafted poly(methyl)‐methacrylate (PEO‐PMMA) with a lithium salt has been examined as a solid electrolyte of an ambient‐temperature rechargeable lithium battery. The electrolyte film was prepared by radical polymerization of PEO‐grafted methacrylate which contained a lithium salt dissolved in poly(ethylene glycol) dimethyl ether. The resulting composite had a high conductivity of 10⁻⁴ S cm⁻¹ at room temperature. The rate of charge transfer at the lithium electrode/polymeric electrolyte interface was high, and the ion transfer in the bulk electrolyte was rate‐determining at high cathodic polarization. The coulombic efficiency of lithium during the charge‐discharge cycle depended on the cycling current density. The average efficiency reached 88% at 50 μA cm⁻² cycling when an Al plate was used as a substrate.