Potassium ion conducting K1 − 2xCdxFeO2 solid electrolytes

New potassium ion conducting solid electrolytes based on potassium monoferrite have been prepared through partial substitution of the divalent cation Cd 2+ on the potassium site, and their properties have been investigated. The introduction of cadmium cations sharply increases the electrical conductivity of KFeO 2 over the entire temperature range studied. In addition to the maximum in conductivity at the boundary of the K 1 − 2 x Cd x FeO 2 solid solution, there is a maximum at a higher cadmium content ( x = 0.30–0.35). The possible origins of this maximum are discussed.