MEA design for low water crossover in air-breathing DMFC

The water crossover behavior in air-breathing direct methanol fuel cell (DMFC) was studied with varying structural variables of membrane electrode assembly (MEA), such as existence of microporous layer (MPL) in cathode diffusion layer, hydrophobicity of cathode backing layer, and membrane thickness. Water crossover from anode to cathode was lowered by the introduction of MPL to cathode backing layer, the reduction of hydrophobicity of cathode backing layer, and the reduction of membrane thickness. To account for the observed water crossover behavior, water back flow caused by the hydraulic pressure difference between the cathode and anode was considered. It was also found that the methanol crossover was lowered with the reduction of water crossover. The MEA designed for low water crossover revealed improved stability under continuous operation. (c) 2007 Elsevier Ltd. All rights reserved.