Composite Solid Electrolyte Composed of 3D Ceramic Ion Transport Channel and in-Situ Formed Polymer Matrix

Abstract

Rechargeable lithium-ion batteries (LIBs) with high energy density and excellent cycling performance have been widely used as portable power supplies for consumer electronics. In recent years, LIBs have expanded their applications to electric vehicles (EVs) and large energy storage systems (ESSs). Existing LIBs use liquid electrolytes, which have safety issues such as inflammability, leakage, and explosion. All-solid-state lithium-ion batteries (ASSLIBs) using various solid electrolytes, such as inorganic electrolytes and polymer electrolytes, have been extensively studied to alleviate safety issues and improve energy density. In addition, composite solid electrolytes (CSEs), which combine the advantages of ceramic and polymer electrolytes, are of particular interest. However, CSE based on a polymer matrix has low ionic conductivity at room temperature, making it difficult to use as an electrolyte for high-performance ASSLIB. In this study, we designed a highly efficient 3D LAGP framework for lithium ion transport that enhances the overall conductivity of CSE. This stiffer 3D LAGP structure also inhibits the growth of Li dendrites. The polymer component of CSE is manufactured using thermal polymerization of vinyl ethylene carbonate (VEC). In addition, excellent electrode-electrolyte interface properties were achieved using in-situ thermal polymerization technology. The optimized CSE exhibited high ionic conductivity of 0.79 mS cm-1 and excellent potential stability up to 5.09 V vs. Li/Li+ at 30 °C. The Li/CSE/NCM811 cells showed excellent rate performance and cycling potential. Therefore, a CSE composed of a 3D LAGP framework and a VEC-based polymer can be used as a potential electrolyte for ASSLIBs.