Improvement in Direct Methanol Fuel Cell Performance by Treating the Anode at High Anodic Potential
NATIONAL RENEWABLE ENERGY LAB GOLDEN CO
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This work investigates the effect of a high anodic potential treatment protocol on the performance of a direct methanol fuel cell DMFC. DMFC membrane electrode assemblies MEAs with PtRuC Hi-spec 5000 anode catalyst are subjected to anodic treatment AT at 0.8 V vs. DHE using potentiostatic method. Despite causing a slight decrease in the electrochemical surface area ECSA of the anode, associated with ruthenium dissolution, AT results in significant improvement in DMFC performance in the ohmic and mass transfer regions and increases the maximum power density by w15. Furthermore, AT improves the long-term DMFC stability by reducing the degradation of the anode catalyst. From XPS investigation, it is hypothesized that the improved performance of AT-treated MEAs is related to an improved interface between the catalyst and Nafion ionomer. Among potential explanations, this improvement may be caused by incorporation of the ionomer within the secondary pores of PtRuC agglomerates, which generates a percolating network of ionomer between PtRuC agglomerates in the catalyst layer. Furthermore, the decreased concentration of hydrophobic CF2 groups may help to enhance the hydrophilicity of the catalyst layer, thereby increasing the accessibility of methanol and resulting in better performance in the high current density region.
- Electrical and Electronic Equipment
- Electrochemical Energy Storage