Designing a membrane electrode assembly for weakly humidity-dependent proton exchange membrane fuel cells

Abstract

Currently, most proton exchange membrane fuel cells (PEMFCs) must operate under high humidification conditions. Developing low-humidity PEMFCs is significantly important for application of PEMFCs in different environments. In this work, we propose a PEM-free approach to fabricate an integrated membrane electrode assembly (i-MEA) by doctor blade coating of an ionomer repeatedly. The results show that the PEM-free method significantly reduces the ohmic impedance of the interface by about 30% at 0.4 A cm⁻², compared to the GDL-MEA prepared by the traditional GDE method. Importantly, when the relative humidity is reduced to 30%, the peak power density of the i-MEA has no significant effect, while the performance of the GDL-MEA decreases by about 30.76%. In addition, this work reveals that a favorable PEM/CL interface will improve proton transport and reverse diffusion of water, while a modified GDL/CL interface is beneficial to mass transfer at high current density. All in all, this work provides a new approach for the development of affordable, high-performance MEAs at low humidity.