Channel engineering of hydroxide ion exchange polymers for electrochemical devices

Abstract

Anion exchange membrane (AEM) fuel cells and electrolyzers are of interest because they have potential advantages over their acidic counterparts for the production and storage of renewable energy. AEM devices operate under high pH conditions where electrokinetics become more facile and allow for the use of non-noble catalysts. Furthermore, the membranes and ionomers can be made from inexpensive precursor materials which significantly drive down costs. A solid hydroxide ion conducting block copolymer AEM based on the vinyl addition polymerization of norbornene has been synthesized with efficient, phase segregated ion conduction channels, a chemically and thermally stable all-hydrocarbon backbone, and a mechanically robust supporting matrix. Light cross-linking was introduced to enable the use of polymers with high ion exchange capacity while maintaining reasonable water uptake and swelling. In this work, this newly developed class of polymers was extensively characterized and tested in fuel cells and electrolyzers to understand the relationship between polymer properties and device performance.