Effect of Diffusion-Layer Morphology on the Performance of Solid-Polymer-Electrolyte Direct Methanol Fuel Cells

Abstract

The performance of solid-polymer-electrolyte direct methanol fuel cells (SPE-DMFCs) is substantially influenced by the morphology of the gas diffusion-layer in the catalytic electrodes. Cells utilising gas diffusion-layers made with high surface-area Ketjen Black carbon, at an optimised thickness, show better performance compared with cells utilising Vulcan XC-72 carbon or ‘acetylene black’ carbon in the diffusion-layer. The cells with a hydrophilic diffusion-layer on the anodes and a hydrophobic diffusion-layer on the cathodes yield better performance. The cells with oxygen or air as the oxidant gave power density of 250 or 105 mW cm^ - ^2, respectively, at an operational temperature of 90 °C and 2 bar pressure