Performance of DMFCs prepared by hot-pressed MEA and catalyst-coated membrane

Abstract

The effect of the fabrication methods of the conventional hot-pressed membrane-electrode assembly (hot-pressed MEA) and catalyst-coated membrane (CCM) on the utilization efficiency of Pt electrocatalysts, methanol crossover and performance of direct methanol fuel cells (DMFCs) is studied under the condition of the same Pt electrocatalyst loading. Cyclic voltammetric and electrochemical impedance studies showed that the cell with CCM exhibited significantly higher electrochemical surface area and lower electrode polarization resistance for the methanol oxidation reaction, in comparison to that with the hot-pressed MEA. Compared with the hot-pressed MEA, the methanol crossover of the cell with CCM is decreased by 55% and the power density of DMFC is enhanced by 36%. The improvement of the DMFCs with CCM is probably due to the significantly higher electrochemical reaction sites and the increased three-phase boundaries through the reduction in the loss of the Pt electrocatalyst in the gas diffusion layers and enhanced electrode/membrane interface.