Polypyrrole nanowire networks as anodic micro-porous layer for passive direct methanol fuel cells

Polypyrrole nanowire networks (PPNNs), as anodic micro-porous layer (MPL) of passive direct methanol fuel cells (DMFCs), are grown in-situ on the surface of carbon paper through an electrochemical polymerization. Passive DMFC with the novel MPL achieves a 28.3% increment in maximum power density from 33.9 mW cm^-2 to 43.5 mW cm^-2 compared with the conventional layer with similar PtRu(1:1) loading of 2.0 mg cm^-2 and operating with 4 M methanol solution at 25 °C. When the PtRu loading is decreased to 1.0 mg cm^-2, the maximum power density of the DMFC still reaches 34.3 mWcm^-2, which shows a comparative value with the conventional layer. The enhanced performance should be ascribed to the introduction of PPNNs, significantly improves catalyst utilization and mass transfer of methanol on the anode.