Characterisation of MF-BaF₂-CaH₂-Al₂O₃ (M=Li, Na) hydrofluorides based on fuel cell studies

Electrical properties of hydrofluorides, MF-BaF₂-CaH₂-Al₂O₃ (M=Li, Na), were investigated based on fuel cell measurements. Excellent proton conduction was discovered in MF-BaF₂-CaH₂-Al₂O₃ (M=Li, Na) electrolytes. The proton conductivity is of the order of 10^-2-10^-1 S cm^-1 for temperatures above 600°C. Proton conduction was found to dominate the fuel cell process although there was always influence from hydride ions, H^-, which may trap proton transport and lower the fuel cell voltage. Fuel cell studies clearly depict the effects and behaviour for different mobile ion species. These new materials have significant importance for both fundamental and applied research.