Membrane-electrode unit for direct methanol fuel cells (DMFC)

摘要

The invention relates to a membrane electrode unit (MEU) for electrochemical apparatuses, in particular for direct methanol fuel cells (DMFC). The membrane electrode unit contains backings (i.e. gas diffusion layers) on the anode side and cathode side, which have a different water tightness (WT). The anode backing must have a lower water tightness (i.e. a higher water permeability) than the cathode backing, where WT_AnodeWT_Cathode. The anode backing preferably has no compensating layer (microlayer), has a lower content of water repellent (from 2 to 10 wt.-%, based on the total weight) and has a higher total pore volume (VTot) than the cathode backing. The membrane electrode units produced have a substantially improved performance in DMFC fuel cells which are operated with aqueous methanol solution.