Intermediate temperature fuel cells with electrolytes based on oxyacid salts

Electrolyte materials based on oxyacid salts are a new type of solid ionic conducting system where both cations and protons are mobile. These materials have a face-centred cubic structure. Two different proton coordination states and conduction mechanisms have been recognized in this system. The proton conduction has been used for intermediate temperature fuel cells (ITFC). ITFCs using materials based on nitrate salts as electrolytes are successful, the best fuel cell performance is a current density of 300 mA cm² at 0.75 V. There are still some technical problems to be solved, such as the coexistence of electrode and electrolyte materials, etc., in these fuel cells, and an improvement of the electrode materials is needed for a better performance of the practical fuel cells.