Preparation of Thin Cation-Exchange Membranes for Redox-Flow Battery using Glow-Discharge Plasma Process

Abstract

Ultra-thin films possessing sulfonic ester groups as a precursor ofcation-exchange membranes for redox-flow battery were prepared bypolymerization of methyl benzenesulfonate and 1,3-butadiene mixture in aglow discharge plasma. The influence of RF power on the decomposition ofsulfonic acid groups in glow-discharge plasma was investigated and theplasma-polymerization mechanism was discussed. The sulfonic ester groupswere transformed to lithium sulfonates by the reaction with lithiumiodide. The sulfonate cation-exchange membrane of 0.7 mu m thickness hadlow membrane resistance per unit area of 0.40 Omega cm(2)(ionicconductivity = 1.8 x 10(-4) S cm(-1)).