The proton exchange membrane water electrolyzer (PEMWE) is a crucial device for hydrogen production, both currently and in the future, due to its environmentally friendly, safe, efficient, and long-lasting characteristics, as well as its rapid start-up capabilities, which confer significant commercial value. Proton conduction resistance of the anode catalyst layer for a PEMWE is an important  impedance component that affects the performance of PEMWE. In trying to obtain the accurate proton conduction resistance, this study conducts experiments based on the different relative humidities, and applied voltages. The results indicate that the minimum proton conduction resistance was achieved under the conditions of 100% anode  relative humidity, 148% cathode relative  humidity, and an applied testing voltage of 1.0-1.2 V. Moreover, the anode catalyst layer of the electrolyzer with a Nafion content of 10% exhibits low proton conduction resistance and optimal performance.

PEMWE, proton conduction resistance, relative humidity, applied voltage, Nafion content