Microporous layers incorporated with polyaniline@titanium dioxide composite for improving performance in proton exchange membrane fuel cells

The development of hydrophilic-modified gas diffusion layer (GDL) has become a prerequisite for enhancing the performance of proton exchange membrane fuel cells (PEMFCs) at various humidity conditions, especially at low humidity. In this paper, a novel hydrophilic-modified GDL was prepared by doping polyaniline@titanium dioxide (PANI@TiO 2 ) composite as a conductive component in MPL. This composite had been demonstrated to have a core–shell structure with advantageous properties such as enhanced conductivity, stability, and obvious hydrophilicity. The single cell tests demonstrated that the modified GDL presented better performance than conventional GDL at various relative humidities (RHs) conditions (40 ∼ 100 %), especially at low humidity. The incorporation of this composite resulted in the increased proportions of mesopores and micropores, reaching maximum values of 16.21 % and 0.51 %, respectively, at a content of 5 %. The maximum power density was increased by 54.52 % compared to the conventional GDL at 70 %RH. This enhancement was attributed to the powerful wettability and pore size distribution modification of PANI@TiO 2 composite. The findings indicated that the remarkable water retention ability of PANI@TiO 2 composite enhanced hydration processes, which offered a practical approach to develop hydrophilic-modified GDLs for PEMFCs applications.