New type of potassium ion conducting solid based on lanthanum oxysulfate

A new type of potassium ion conducting polycrystalline solid electrolyte, (1 − x)La2O2SO4 − x(0.8K2SO4 − 0.2CaSO4), with the high ion conductivity at the elevated temperature region was developed by doping potassium and calcium sulfates into the thermally stable lanthanum oxysulfate. Among the samples of the single phase La2O2SO4, the 0.8La2O2SO4 − 0.2(0.8K2SO4 − 0.2CaSO4) (x = 0.2) shows the highest ion conductivity reaching values potentially suitable for applications, i.e. σ is greater than 10−2 S cm−1 above 800 °C.