Br− anion-conducting properties in La1−xMxOBr1−x solid (M=Ca, Sr)

A new Br− anion-conducting solid electrolyte with a low solubility in water and a high thermal stability at elevated temperatures was developed by selecting lanthanum oxybromide (LaOBr) as a mother solid electrolyte phase. By the partial substitution of La3+ site in LaOBr with divalent Ca2+ or Sr2+, the bromide anion conductivity was greatly enhanced, and the highest Br− ion conductivity of 1.9×10−3 and 1.2×10−4 S·cm−1 was obtained at 873 K for La0.9Sr0.1OBr0.9 and La0.9Ca0.1OBr0.9, respectively. The Br− anion conduction in La0.9M0.1OBr0.9 (M=Ca, Sr) was directly demonstrated by DC electrolysis.