Composite membranes as an electrolyte for high-temperature PEMFCs (proton exchange membrane fuel cells) were prepared by mixing a Nafion polymer matrix and proton-β"-aluminas (H3O+-β"-Al2O3 and NH4 +/H3O+-β"-Al2O3) as inorganic fillers with fast proton conductivity. From the K+-β"-alumina precursor, the aforementioned proton-β"-aluminas were prepared via ion-exchange reactions by a hydrothermal process using an acetic acid solution and ammonium nitrate solution, respectively. Water contact angles of the composite membranes were measured, and the electrical properties of the PEMFCs were analyzed at 80~100 οC under atmospheric pressure. As the filler content increases, the contact angle becomes smaller and thus more hydrophilic. Also, some prepared composite membranes showed a higher cell performance than Nafion® 115 membrane at 80~100 οC.

Keywords: β"-alumina, Solid electrolyte, Composite membrane, High-temperature PEMFCs.