The effect of binder content on the performance of a high temperature polymer electrolyte membrane fuel cell produced with reactive spray deposition technology

• Gas diffusion electrodes produced by reactive spray deposition technology.
• Different PTFE binder and Carbon ratio was investigated.
• Optimal PTFE binder/Carbon ratio was determined to be equal to 0.9.
• Good catalyst dispersion and small, uniform pores led to the best performance.

The effects of polytetrafluoroethylene (PTFE) binder content in the catalyst layer of high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) utilizing phosphoric acid doped Advent TPS® polymer electrolyte membranes (pyridine bearing aromatic polyethers, TPS) has been investigated in terms of both hydrogen/oxygen and hydrogen/air performance. The anode and cathode gas diffusion electrodes (GDE) were fabricated with different PTFE/carbon weight ratios by a flame based process known as the Reactive Spray Deposition Technology (RSDT) method in order to increase the active platinum (Pt) surface area, with a goal of decreasing overall Pt levels to a total loading of 0.1 mg cm−2. The electrodes, prepared with different amounts of PTFE binder, have been tested in a single cell, with a 25 cm2 geometric area, under an operating temperature range of 160–200 °C. Tests measuring the Pt nanoparticle dispersion on the carbon supports, the pore size distribution, and the electrochemical surface area of the catalyst layer were also performed. The best cell performance was achieved with PTFE/carbon weight ratio of 0.9 over the entire range of operating temperatures. This optimal PTFE binder content resulted in well-developed Pt dispersion on the carbon support and small, uniformly sized pores which develop ideal capillary forces for distributing the phosphoric acid electrolyte evenly throughout the catalyst layer. This led to a high number of triple phase boundaries and maximized Pt utilization.