Session 9-1

Abstract

In the last decade, considerable effort has been devoted to develop high performance and durable anion exchange membranes (AEMs) for energy device applications such as alkaline fuel cells and water electrolyzers, and redox flow batteries. When these devices are operated under the alkaline conditions, use of non-precious metal catalysts becomes practical. Although a number of AEMs have been proposed in the literature, chemical and physical stability in alkaline media still remains an issue for long-term, reliable operation of the devices. In the pursuit of more stable, more ion-conductive AEMs, we have developed a series of new polymer structures. Combination of partially fluorinated polymer main chain free from heteroatom linkages such as ether, sulfide, and sulfone, and pendent ammonium head groups contributed to improvement of the stability as well as the ion conductivity of AEMs.[1]  A typical example is QPAF-4 copolymers composed of perfluoroalkylene/phenylene main chain and hexylammonium head groups, which exhibited good membrane forming capability, high hydroxide ion conductivity, alkaline and mechanical stability (Figure 1).[2]  In the present study, we discuss alkaline fuel cell and water electrolysis cell performance of QPAF-4 membrane with commercial and our in-house catalyst materials.[3]  Effect of polymer structure on AEM properties will also be discussed.[4]