Superprotonic conducting phosphate glasses containing water

Fuel cells using H2–O2 offer the potential to minimize atmospheric pollution. Newly developed baria-phosphate glasses containing an appreciable amount of mobile hydrogen ions (protons) as well as molecular water exhibit super proton-conductivity. The new BaO–La2O3–Al2O3–P2O5 glasses exhibit high proton conductivities of 10−2 S/cm at 200 °C and 10−3 S/cm at 25 °C with a low activation energy of 0.17 eV. A H2–O2 fuel cell using this superprotonic glass electrolyte is operable at temperatures from 25 °C to 200 °C even under non-humidified conditions. The protons in oxide glasses have been often considered for a long time to be almost immobile. However, here we show that these superprotonic conductors of phosphate glasses are a good candidate material for viable electrolytes of fuel cells.