Highly branched side chain grafting for enhanced conductivity and robustness of anion exchange membranes

Abstract

As a key component of alkali anion exchange membrane fuel cells, the anion exchange membrane (AEM) needs to have high ionic conductivity and good stability. Herein, highly branched side chain grafted polysulfone AEMs are designed and fabricated via macromolecule-initiated atom transfer radical polymerization of chloromethyl styrene. The highly branched side chain results in increased free volume in the AEM. As a result, the membrane shows significantly improved hydroxide conductivity relative to its un-branched counterpart membrane. Furthermore, the highly branched side chain renders the membrane with better anti-swelling property and improved alkaline stability. These results demonstrate that constructing highly branched side chain architecture is an effective strategy for fabricating AEMs with high conductivity and stability.