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.