Analysis of Hydrogen Feeding to the Anode of a PEMFC By a Transport Impedance Technique

Transport properties in the anode of a PEMFC have been studied with an impedance technique that relates the hydrogen flow rate with the generated current, that we name current modulated hydrogen flow rate spectroscopy (CH2S). Measurements have been carried out under different experimental conditions, including inlet port characteristics, dc current, active area size, gas diffusion electrode type, and water saturation in the electrodes. The Nyquist plots show at least two kinetic processes with different time characteristics, related with anode architecture and/or gas diffusion electrode transport properties. The possibility to use CH2S to study mass transport properties of the gas diffusion electrodes is explored.