Preparation of Li₇P₂S₈X-Type Solid Electrolytes with Complex Anions for All-Solid-State Lithium Battery Applications

Abstract

To improve the energy/power density and safety of all-solid-state lithium batteries (ASSBs), sulfide-based solid electrolytes have recently attracted attention. Li 7 P 2 S 8 X solid electrolytes are believed to show highly comparable ionic conductivity and stability against lithium metal. In this study, complex anion-based Li 7 P 2 S 8 X solid electrolytes were prepared for the first time to achieve good stability against lithium metal anodes. The crystalline structure and the role of complex anions in tuning the crystal structure were analyzed using powder X-ray diffraction techniques. Laser Raman and nuclear magnetic spectroscopy analyses were performed to reveal the structural characteristics of complex anion-based Li 7 P 2 S 8 X solid electrolytes. A m o n g a l l p r e p a r e d s o l i d e l e c t r o l y t e s , t h e Li 7.05 Sn 0.05 P 1.95 S 8 (OH) 0.25 I 0.75 solid electrolyte exhibited the highest ionic conductivity of 4.3 mS cm −1 at room temperature. Cyclic voltammetry and DC polarization analysis were carried out to study the stability of solid electrolytes against lithium metal anodes. Interestingly, complex anion:halogen anion-based solid electrolytes exhibited a high critical current density and a long DC cycle stability (>250 cycles).

High-Conductivity Li2ZrCl6 Electrolytes via an Optimized Two-Step Ball-Milling Method for All-Solid-State Lithium–Metal Batteries

“…Lithium-ion batteries (LIBs) are widely regarded as promising candidates for energy storage applications in various industries. − In recent years, the safety hazard of traditional liquid organic electrolytes in LIBs has promoted the rapid development of all-solid-state lithium–metal batteries (ASSLMBs) for their outstanding safety characteristics and high energy density. − It is widely acknowledged that the critical factor for the advancement of ASSLMBs lies in the development of the solid-state electrolytes (SSEs) , that can fulfill the requirements of high ionic conductivity, mechanical deformability, and a wide electrochemical stability window. − …”