Low methanol crossover and high efficiency direct methanol fuel cell: the influence of diffusion layers

This experimental work aims to investigate the possibility to reduce methanol crossover in DMFC mod- ifying diffusion layer characteristics. Improvements in crossover measurement are firstly proposed, permitting to conclude that in the investigated conditions carbon dioxide flow through the membrane can be neglected. The experimental results evidence that introducing appropriate anode and cathode microporous layers determines: a strong reduction in methanol crossover, approximately 45% at low current density; a considerable increment of efficiency; a moderate decrease of power density. The com- plete experimental analysis demonstrates that methanol transport in both liquid and vapour phases can be controlled modifying properly diffusion layer characteristics in order to increase DMFC efficiency.