Anodic diffusion layer with graphene-carbon nanotubes composite material for passive direct methanol fuel cell

Graphene-carbon nanotubes (G-CNTs) composite material was prepared as the anodic micro porous layer (MPL) carbon material to fabricate the anodic diffusion layer for a passive direct methanol fuel cell (DMFC). The crack-free anodic MPL was obtained with the G-CNTs, leading to significant improvement in the cell's performance. The maximum power density of∼41.6mWcm−2 at a temperature of ∼25 °C was achieved using the G-CNTs as the anodic MPL material. H adsorption/desorption and CO stripping indicated that the enhanced performance of the passive DMFC by adding G-CNTs in anodic MPLs could be attributed to the improvement in catalyst utilization. CO stripping measurements showed∼36.1% increase in the electrochemical active surface area of the electrode with G-CNTs within MPL than that of Vulcan XC-72R carbon. AC impedance data demonstrated that the charge transfer resistance of the anode reaction decreased with G-CNTs as the anodic MPL material.