Enhanced electrochemical performance of PEO/Li6.4Ga0.2La3Zr2O12 composite polymer electrolytes

All-solid-state lithium batteries (ASSLBs) are regarded as the most promising alternative to traditional liquid lithium-ion batteries due to their high-energy density and excellent safety. As an important part of ASSLBs, composite polymer electrolytes (CPEs) with excellent comprehensive performance have attracted wide attention from researchers. Herein, a series of CPEs were prepared by employing Li 6.4 Ga 0.2 La 3 Zr 2 O 12 (LGLZO) submicron particles with cubic phase as fillers in polyethylene oxide (PEO) matrix. The tape-casting method was employed to prepare PEO-LiTFSI-x% LGLZO (CPE-x, where x  = 0–80). In these CPE-x, the CPE-40 exhibits elevated ionic conductivity (6.20 × 10 −5 S cm −1 at 20 °C and 1.88 × 10 −4 S cm −1 at 60 °C), attractive Li + transference number (0.31 at 60 °C), low activation energy barrier of lithium-ion migration, wide electrochemical window, and high critical current density of 1.3 mA cm −2 . Furthermore, the LiFePO 4 | CPE-40 | Li batteries deliver outstanding cycle performance (capacity retention of 85.43% after 225 cycles at 0.2C and 60 °C) and rate performance. These results show that the PEO-base solid-state electrolytes filled with submicron LGLZO particles possess a broad application prospect.