Superionic glass-ceramic electrolytes for room-temperature rechargeable sodium batteries

Abstract

Innovative rechargeable batteries that can effectively store renewable energy, such as solar and wind power, urgently need to be developed to reduce greenhouse gas emissions. All-solid-state batteries with inorganic solid electrolytes and electrodes are promising power sources for a wide range of applications because of their safety, long-cycle lives and versatile geometries. Rechargeable sodium batteries are more suitable than lithium-ion batteries, because they use abundant and ubiquitous sodium sources. Solid electrolytes are critical for realizing all-solid-state sodium batteries. Here we show that stabilization of a high-temperature phase by crystallization from the glassy state dramatically enhances the Na+ ion conductivity. An ambient temperature conductivity of over 10−4 S cm−1 was obtained in a glass-ceramic electrolyte, in which a cubic Na3PS4 crystal with superionic conductivity was first realized. All-solid-state sodium batteries, with a powder-compressed Na3PS4 electrolyte, functioned as a rechargeable battery at room temperature. Rechargeable solid-state batteries are promising sources of energy for a range of applications. Hayashiet al. examine the electrochemistry of solid-state sodium batteries, and present an electrolyte that operates at room temperature.