Li0.35La0.55TiO3 nanofibers filled poly (ethylene carbonate) composite electrolyte with enhanced ion conduction and electrochemical stability

Abstract A solid electrolyte with flexible and high ion conductivity is of great concern in high-performance all-solid-state lithium batteries. Using flexible polymer matrix combining with conductive ceramics filler is a convenient and effective strategy to integrate high ion conductivity into flexibility. Here, flexible solid electrolytes with continuous Li-ion transfer pathways were constructed by combining the Li0.33La0.557TiO3 (LLTO) nanofibers with poly (ethylene carbonate) (PEC) matrix. The effect of the content and diameter of the LLTO nanofibers on the ionic conductivity, electrochemical stability, and glass transition temperature of the composite electrolyte was investigated. The results are demonstrated that adding LLTO nanofibers into the PEC improves ionic conductivity and electrochemical stability of the electrolytes. The composite electrolyte containing 5 wt.% of LLTO nanofibers shows the maximum ionic conductivity of 3.48 × 10−3 S cm−1 at 85 °C with the electrochemical stability window of 5.1 V when the diameter of nanofiber is 250 nm. In addition, the composite electrolyte is flexible with elongation at breaking up to 362%.