Protonic ceramic electrochemical cells for hydrogen production and electricity generation: exceptional reversibility, stability, and demonstrated faradaic efficiency

We demonstrate excellent performance and durability at intermediate temperatures (500–650 °C) upon reversible operation of an electrochemical cell incorporating a proton-permeable, high-activity mixed conducting oxide as the air electrode, a highly proton-conductive and chemically stable perovskite oxide as the electrolyte, and a composite of Ni and the electrolyte as the fuel electrode.