Effect of membrane electrode assembly fabrication method on the single cell performances of polybenzimidazole-based high temperature polymer electrolyte membrane fuel cells

Abstract

Membrane electrode assemblies (MEAs) for a high temperature polymer electrolyte membrane fuel cell (HTPEMFC) were fabricated using acid-doped polybenzimidazole (PBI) as the electrolyte membrane and polytetrafluoroethylene (PTFE) as the electrode binder. PTFE concentrations of 20, 30, and 45 wt% in the electrode were evaluated to determine the optimal binder content. Additionally, the influence of applying a pressing process during MEA fabrication on the electrode performance was examined. When MEA was prepared without the pressing process, the electrode containing 20 wt% PTFE exhibited the best cell performance (338 mA cm−2 at 0.6 V). However, when MEA was prepared with the pressing process, the electrode containing 45 wt% PTFE exhibited the best cell performance (281 mA cm−2 at 0.6 V). This result is because of the inclusion of the pressing process, as gas permeability is hindered by the transfer of excess phosphoric acid from the electrolyte membrane to the electrodes.