Design and Synthesis of K-Ion Solid Electrolytes Based on Antiperovskites and Chalcogenides

Potassium batteries with organic liquid electrolytes, including K-ion, K–O 2 , and K–S batteries, have emerged as promising candidates for large-scale energy storage due to the high earth abundance and low redox potential of potassium (−2.93 V versus SHE). However, the issues brought by using liquid electrolyte still hinder the development of K-batteries. The utilization of solid electrolytes will not only have the commonly recognized benefits in suppressing dendritic metal plating and enhancing battery safety, but also in blocking oxygen or sulfur crossover from the cathode. In this presentation, I will present our recent progress in developing K-ion solid electrolytes based on antiperovskites, K3OX (X=Cl, Br and I) and chalcogenides (K3SbS4 and K3SbSe4). Among them, K 2.92 Sb 0.92 W 0.08 S 4 exhibits high conductivity of 1.4×10 −4 S cm −1 at 40 °C, which is among the best reported potassium-ion conductors at ambient temperature.Their applications in room-temperature K-S and K-O2 batteries have been successfully demonstrated.