Imidazolium-Functionalized Polymer Membranes for Fuel Cells and Electrolyzers

Imidazolium-functionalized styrenic copolymers have been widely studied as candidates for use as anion exchange membranes in carbon dioxide and water electrolysis systems. Recent new developments in catalytic electrode materials suggest that electrolyzers based on this technology will be commercially viable. Nevertheless, important aspects of the physicochemical behavior of these membrane materials, especially transformations occurring upon activation in strongly alkaline media, remain incompletely understood. We discuss results from 1- and 2-D NMR, IR, and IEC studies of N-methylimidazolium-functional styrenic copolymer membrane materials recovered after activation by exposure to 1M KOH solution and reacidification in HCl. The work sheds some new light on the chemistry occurring during the handling process.