A cost-effective and humidity-tolerant chloride solid electrolyte for lithium batteries

Abstract

Li-ion-conducting chloride solid electrolytes receive considerable attention due to their physicochemical characteristics such as high ionic conductivity, deformability and oxidative stability. However, the raw materials are expensive, and large-scale use of this class of inorganic superionic conductors seems unlikely. Here, a cost-effective chloride solid electrolyte, Li ₂ZrCl ₆, is reported. Its raw materials are several orders of magnitude cheaper than those for the state-of-the-art chloride solid electrolytes, but high ionic conductivity (0.81 mS cm ^–1 at room temperature), deformability, and compatibility with 4V-class cathodes are still simultaneously achieved in Li ₂ZrCl ₆. Moreover, Li ₂ZrCl ₆ demonstrates a humidity tolerance with no sign of moisture uptake or conductivity degradation after exposure to an atmosphere with 5% relative humidity. By combining Li ₂ZrCl ₆ with the Li-In anode and the single-crystal LiNi _0.8Mn _0.1Co _0.1O ₂ cathode, we report a room-temperature all-solid-state cell with a stable specific capacity of about 150 mAh g ^–1 for 200 cycles at 200 mA g ^–1.

Abstract

Stable inorganic solid electrolytes are instrumental in developing high-voltage Li metal batteries. Here, the authors present the synthesis and electrochemical energy storage properties of a cost-effective and humidity-tolerant chloride solid electrolyte.