One‐pot aprotic solvent‐enabled synthesis of superionic <scp>Li‐argyrodite</scp> solid electrolyte
Young Jin Heo, Seung‐Deok Seo, Suk‐Ho Hwang, Sun Hee Choi, Dong‐Wan Kim
Abstract
Summary Li‐argyrodite phase Li 6 PS 5 Cl is a promising solid electrolyte (SE) with potential applications in all‐solid‐state batteries (ASSBs). Conventional SE synthesis methods such as high‐energy ball‐milling and solid‐state synthesis require a significant amount of energy. Consequently, in recent years, several studies have been conducted on developing liquid phase methods for mass‐producing SEs. One such liquid phase method uses tetrahydrofuran (THF, an aprotic solvent) and ethanol (EtOH, a protic solvent) to synthesize Li 6 PS 5 Cl. However, the synthesized SE contains impurities that are generated by reactions between EtOH and PS 4 3− . In this study, we present a novel one‐pot liquid phase method for synthesizing Li 6 PS 5 Cl using THF. The synthesized SE had a high ionic conductivity (2.03 mS·cm −1 ) and low electronic conductivity (7.44 × 10 −8 S·cm −1 ). Notably, it had few impurities and was essentially composed of a single phase. Furthermore, an ASSB cell composed of LiNbO 3 ‐coated LiNi 0.6 Mn 0.2 CoO 2 (NMC622)/Li 6 PS 5 Cl/Li‐In, which contained the synthesized SE, exhibited a high discharge capacity of 156 mAh·g −1 . Therefore, the liquid phase method proposed herein can be used to synthesize SEs, and can help realize mass production and commercialization.