MnO2 Nanowire Thin Mesh with Enhanced Mass Transfer as Hydroxide Exchange Membrane Fuel Cell Cathode

Hydroxide exchange membrane fuel cells (HEMFCs) are promising due to the potential use of non‐precious metal catalysts. However, the performance of HEMFCs based on non‐precious catalysts is still unsatisfactory, and one reason for this is hindered mass transfer in the catalyst layer. Here, we employ a hydrothermal method to grow in situ a MnO2 nanowire thin mesh (NTM) catalytic layer on the gas diffusion electrode. The HEMFC prepared with MnO2 NTM cathode achieves a peak power density of 425 mW cm−2, surpassing the performance of an HEMFC prepared using the traditional powder catalyst spraying method by 4 times. High‐frequency resistance and limiting current tests indicate that the MnO2 NTM reduces ohmic resistance and improves mass transfer, thereby enhancing the HEMFC performance. Furthermore, the peak power density of the HEMFC is increased to 626 mW cm−2 by depositing additional active Co3O4 nanoparticles on the MnO2 NTM. These findings demonstrate that an interconnected and porous catalyst layer structure is beneficial for improving mass transfer properties, which in turn enhances HEMFC performance.