Development trends of direct methanol fuel cells

DMFC is one of the fuel cells that generate electricity using aqueous methanol solution as a fuel and oxygen or air as an oxidizing agent. By operation of DMFC, methanol is oxidized by oxygen to produce carbon dioxide and water. A single cell of DMFC is composed of an MEA that is held between separators. MEA is manufactured by laminating anode and cathode on both sides of polymer electrolyte membrane which is made of sulfonized perfluorocarbon polymer or hydrocarbon polymer. Recently limiting current has increased up to 600 mA/cm(2) owing to the advance in MEA technology. DMFC can be downsized because they use liquid fuel directly, which is more preferable for applications such as portable and mobile use. However, there are many technological problems that should be overcome to realize DMFC system to be used for those applications. Especially, a breakthrough in materials research should be necessary in order to decrease methanol crossover and to improve catalytic activity.