Atomic-layer-deposited TiO2 on cathode gas diffusion layer for low humidity operation in hydrogen fuel cells

External humidifying system is generally needed for the activation of membrane and catalyst layer, but it is continuously considered as barrier to commercialize polymer electrolyte hydrogen fuel cells (PEFCs). In this study, ultrathin layer of hydrophilic TiO2 was coated on hydrophobic microporous layer of gas diffusion layer (GDL) at the cathode to maintain the power performance of PEFCs under extremely low cathode humidification operation. The TiO2 layers of various cycles were precisely deposited on GDL using atomic layer deposition to minimize both the losses of electrical conductivity and surface area of microporous layer. We observed that TiO2 coated GDL resulted in higher performance than as-received GDL at low humidity operation. (C) 2012 Elsevier B.V. All rights reserved.