The possibility of high efficiency fuel cells based on proton conducting oxide electrolyte thin films

Abstract

Protonic solid oxide fuel cells (H⁺-SOFCs) have limited application below 500 ℃ owing to their high ohmic and polarisation resistances. Hence, efforts are ongoing to develop advanced fuel cells based on semiconductor device science. Here, we demonstrate that hydrogen-permeable metal-supported fuel cells (HMFCs) exhibit improved energy conversion efficiency at relatively low temperatures due to the retardation of secondary oxide ion conduction at the oxide/metal heterointerface. The electrolyte membrane in HMFCs is forced to gain extra protons to compensate for the charge from the oxide ions accumulating via blocking, resulting in extremely high proton conductivity. Simultaneously, the heavily hydrated membrane pumps out the cathode-side protons during cell operation. Hence, HMFCs can operate at high efficiency even at relatively low temperatures.