Developments in membranes, catalysts and membrane electrode assemblies for direct methanol fuel cells (DMFCs)

Direct methanol fuel cells (DMFCs) are particularly attractive as portable power sources because they use liquid methanol fuel which is easily manageable and has a high energy storage density. However, DMFCs present certain major challenges: the sluggish methanol oxidation reaction at the anode and oxygen reduction reaction at the cathode and methanol crossover through the membrane from the anode to the cathode, all of which lead to dramatic performance losses. The commercialization of DMFC has been hindered by these factors, as well as the high costs of the Pt-based catalyst and perfluorinated membrane currently used. This chapter, after outlining the fundamental aspects of DMFC operation, focuses on the design and developments of membranes, electrocatalysts, catalyst layer and membrane electrode assembly (MEA) structure to address these technical challenges and reduce the cost.