Optimization of gas diffusion electrode for polybenzimidazole-based high temperature proton exchange membrane fuel cell: Evaluation of polymer binders in catalyst layer

Gas diffusion electrodes (GDEs) prepared with various polymer binders in their catalyst layers (CLs) were investigated to optimize the performance of phosphoric acid doped polybenzimidazole (PBI)-based high temperature proton exchange membrane fuel cells (HT-PEMFCs). The properties of these binders in the CLs were evaluated by structure characterization, electrochemical analysis, single cell polarization and durability test. The results showed that polytetrafluoroethylene (PTFE) and polyvinylidene difluoride (PVDF) are more attractive as CL binders than conventional PBI or Nafion binder. At ambient pressure and 160 °C, the maximum power density can reach ∼ 0.61 W cm⁻² (PTFE GDE), and the current density at 0.6 V is up to ca. 0.52 A cm⁻² (PVDF GDE), with H₂/air and a platinum loading of 0.5 mg cm⁻² on these electrodes. Also, both GDEs showed good stability for fuel cell operation in a short term durability test.