Cultivating titanium dioxide nanoarrays on gas diffusion layer for advancing self-humidifying proton exchange membrane fuel cell

Ensuring consistent and reliable operation of proton exchange membrane fuel cells (PEMFCs) in low humidity environments is crucial for their real-world application. In this study, we introduce an innovative approach to address this challenge by employing a uniform growth of single crystal rutile titanium dioxide nanoarray (TiO 2 NRs) on the gas diffusion layer (GDL) through a seed coating hydrothermal method, which leads to the creation of a novel self-humidifying membrane electrode assembly (MEA). The effects of TiO 2 NRs on the wettability, resistance, performance and stability of the MEA were investigated, and the loading capacity was optimized. The results reveal that the integration of TiO 2 NRs into the MEA offers superior performance under 21 % relative humidity (RH) conditions compared to conventional doping TiO 2 nanoparticles into the catalyst layer (CL). By optimizing the TiO 2 NRs loading to 0.32 mg cm −2 of the MEA, a remarkable peak power density of 689.36 mW cm −2 was achieved at low humidity, equivalent to 93 % of the performance observed at 100 % RH. In addition, a 24-hour continuous test at constant voltage (0.6 V) showcased the exceptional stability of the TiO 2 NRs-based MEA, which is attributed to the unique water retention capabilities of the TiO 2 NRs within the CL, facilitating enhanced regulation of water balance within the PEMFC.