A Direct Methanol Alkaline Fuel Cell Based on Poly(phenylene) Anion Exchange Membranes

Abstract

The Investigation of the performance of poly(phenylene) based anion exchange membranes (AEMs) in a direct methanol fuel cell is reported. The fuel cell performances were tested with different anode gas diffusion layers as a function of concentrations of fuel and electrolyte using two commercially available platinum catalysts supported on carbon. Normalized current density values demonstrated good performance for a poly(phenylene) AEM, with a cation consisting of six methylene spacers attached to a trimethyl ammonium group, with a maximum current density of 11.8 mA cm−2 mg−1 in a KOH free fuel. The platinum catalyst (46%) from Tanaka showed a better performance (10.4 mA cm−2 mg−1) compared to the platinum catalyst from E-TEK (5.1 mA cm−2 mg−1) in 1M methanol fuel feed under identical conditions. We observed that the MEA with a Zoltek gas diffusion layer on the anode showed the best performance (226 mA cm−2 and 53.8 mW cm−2) in the presence of KOH, suggesting that a hydrophilic gas diffusion layer plays a significant role in improving the fuel cell performance. A durability test for a MEA in 1M methanol and 1M KOH for 67 h showed an overall degradation rate of 400 μV h−1.