Investigation of the microstructure, mechanical behavior, and electrochemical performance of dual‑polymer‑based composite solid‑state electrolytes

Abstract

Solid polymer electrolytes (SPEs) and inorganic solid electrolytes (ISEs) represent the two primary categories of solid-state electrolytes, yet both exhibit inherent limitations. Composite solid polymer electrolytes (CSPEs), which incorporate inorganic fillers into a polymer matrix, combine the advantages of both components and have emerged as a promising solution. This study employs a dual-polymer matrix composed of PVDF-HFP and PPC, reinforced with varying weight percentages of LLZTO (Li6.4La3Zr1.4Ta0.6O12) and LATP (Li1.3Al0.3Ti1.7P3O12) fillers. The designed composite structure leverages the high ionic conductivity and mechanical strength of LLZTO, along with the excellent electrochemical stability of LATP, creating a synergistic effect that enhances mechanical integrity and prevents brittleness. We systematically investigated the microstructure, mechanical properties, and electrochemical performance of the prepared CSPEs. The results indicate that the incorporation of LLZTO and LATP significantly improves ionic conductivity, mechanical strength, and interfacial stability. This work provides an in-depth analysis of the mechanisms by which inorganic fillers enhance electrolyte performance, offering valuable insights for the design of high-performance, durable, and safe solid-state lithium batteries (SSLBs).