Dual-layer catalyst layers for increased proton exchange membrane fuel cell performance

The use of a dual-layer cathode catalyst layer improves the performance of proton exchange membrane fuel cells. To generate single and dual-layer catalyst layers between the gas diffusion media and proton exchange membrane electrolyte, two commercial carbon-supported platinum catalysts with either a high microporosity carbon (Ketjen Black EC-300J) or a low porosity carbon (XC-72 Vulcan carbon) are utilized. We discovered that dual-layer cathode catalyst layers boost maximum power of fuel cells regardless of carbon porosity directionality, with either high surface area carbon at the proton exchange membrane electrolyte or gas diffusion media interface. At 25% relative humidity, a condition that generally inhibits fuel cell performance, a 20% performance boost is realized when using dual-layer cathode CLs. The electrochemical impedance spectroscopy results indicate that cathodes with dual-layer catalyst layer aid in water management due to lower kinetic activity losses of the Pt and improved hydration of the proton exchange membrane electrolyte. • Goal was to fabricate a dual-layer cathode CL with a porosity gradient. • Catalyst layer microstructure is determined by SEM. • Catalyst layer porosimetry is determined by N 2 adsorption isotherm. • A 20% performance increase is achieved at 25% RH with the Dual-layer cathode CL. • PEMFC performance is improved regardless of the porosity gradient direction.