LiTa₂PO₈-Based Polymer–Ceramic Electrolyte Paved the Way to High-Performance Solid-State Lithium Metal Batteries

Abstract

Solid composite electrolytes, leveraging the advantages of both ceramics and polymers, are emerging as a viable alternative to liquid electrolytes in all-solid-state lithium metal batteries. Here, we have developed a polymer−ceramic composite electrolyte with an area-specific resistance of ∼94 Ω cm 2 at room temperature (RT) by the solution casting method. A Li-ion conducting LiTa 2 PO 8 ceramic with an RT bulk conductivity of ∼3.2 × 10 −4 S cm −1 was synthesized to act as an active filler in a PEO/PVDF-HFP polymer matrix complexed with LiTFSI salt to obtain a polymer−ceramic composite electrolyte. The symmetric lithium cell with the optimized electrolyte exhibited excellent cyclability over 950 cycles at an areal current density of 0.2 mA cm −2 . The full cell with LiFePO 4 cathode and lithium metal anode delivered a specific capacity of ∼115 mAh g −1 with ∼85% capacity retention after 500 cycles at 1C at RT, making it a viable alternative to be adopted in Li-ion batteries for room temperature applications.