Composite membranes based on heteropolyacids and their applications in fuel cells

Abstract

Heteropolyacids (HPAs) are a class of inorganic materials that have been widely used as additives to enhance the performance of fuel cell membranes, recently. This chapter covers the use of HPAs in the preparation of proton exchange membranes (PEM) for polymer electrolyte membrane fuel cells (PEMFCs). The fundamental aspects of HPAs and their corresponding salts in addition to various structural configurations such as Keggin, Wells-Dawson, and Lacunar are discussed. The use of HPAs for preparation of membranes for high-temperature PEMFC and direct methanol fuel cell (DMFC) based on the immobilization on various substrates including perfluorinated sulfonic acids (PFSAs), aromatic hydrocarbons, poly(vinyl alcohol) (PVA), and polybenzimidazole (PBI) are reviewed. The research challenges that need to be addressed to bring the new composite membranes to practical application are also discussed.