Solvent-Free Process for Blended PVDF-HFP/PEO and LLZTO Composite Solid Electrolytes with Enhanced Mechanical and Electrochemical Properties for Lithium Metal Batteries
Rong‐Ao Tong, Linhui Chen, Bingbing Fan, Gang Shao, Ruiping Liu, Chang‐An Wang
Abstract
All solid-state lithium metal batteries are viewed as a potential next-generation energy storage technology due to their high energy density and better safety performance. The study on solid-state electrolytes (SSE) is of crucial importance for the development of technology in this field. Here, we develop a solvent-free preparation and matrix modification process for all-solid-state composite electrolytes (CSEs) based on the blended PVDF-HFP/PEO polymer matrix, and systematically study the effects of the solvent-free process on their properties. The results show that the solvent-free PVDF-HFP/PEO/10 wt % LLZTO solid-state electrolytes (1:1 mass ratio blended polymer matrix) combine the electrochemical and mechanical advantages of both polymers, thus-prepared electrolytes perform excellent tensile strength and ductility (over 500% strain for polymer matrix as well as 170% strain and 4.78 MPa strength for CSEs), and the ionic conductivity can reach ∼6.2 × 10–4 S·cm–1 at 80 °C. At the same time, the electrochemical stability and cycle stability of the electrolytes are enhanced due to the optimized process. The discoloration reaction of PVDF-HFP in composite electrolytes is further studied in this work as well. In addition to excellent performance, the simple process based on the solvent-free method also lays the foundation for scale-up production.