(Invited) Electrochemical Energy Storage and Conversion Devices Incorporating C2-Protected Polybenzimidazoliums and Polyimidazoliums

Alkaline anion exchange membranes (AAEMs) which are capable of conducting hydroxide ions have been investigated in various alkaline based electrochemical energy storage and conversion technologies. Electrochemical systems relying on alkaline-based active components possess unique advantages over their acidic counterparts but at the same time are associated with significant challenges. In our research, we have been investigating C2-protected polybenzimidazolium and polyimidazolium polymers as hydroxide ion conducting polymers, for membranes and ionomer in catalyst layers, because of their stability in caustic conditions, scalability in synthesis, and mechanical strength. As an example of this work, we report on the performance of C2-protected hexamethylterphenyl-polybenzimidazole-based fuel cells in which the content and surface of the carbon support in the cathode catalyst layer is functionalized. We demonstrate that the composition of the cathode catalyst layer plays a large role in determining the performance of these particular anion exchange polymers.