Journal of Applied Electrochemistry, Vol.40, No.1, 29-38, 2010
Pseudo-half-cell measurements on symmetrical catalyst-coated membranes and their relevance for optimizing DMFC anodes
The preparation of catalyst-coated membranes (CCMs) with two anodic catalyst layers (60% PtRu/C as catalyst) using a decal technique and their characterization by pseudo-half-cell measurements using both sides of the CCMs by simply turning the test cell around, allows the characterization of quasi-identical CCMs with a much smaller experimental uncertainty than observed for the classical direct methanol fuel cell (DMFC) testing of membrane electrode assemblies under similar working conditions (5 mV vs. 12 mV at a current density of 140 mA cm(-2)). With this new sensitive tool, we study the influence of the dispersing technology and the Nafion content on the performance of DMFC anodes. While the ionomer content shows a broad optimum between 20 and 40%, the dispersing technology does not have a strong impact on the fuel cell performance under the experimental conditions of this study, but influences strongly the stability of the catalyst slurries and the homogeneity of the electrode coatings.
Keywords:Anode;Catalyst layer;Decal technique;Direct methanol fuel cell;Membrane electrode assemblies;Pseudo-half-cell measurement