Abundant oxygen vacancy nanotube-incorporated composite solid electrolyte boosting long-life all-solid-state batteries

The commercialization of high-energy-density lithium metal batteries relies on the development of novel solid electrolytes with high ionic conductivity, appropriate mechanical strength, and excellent compatibility with electrodes. Herein, poly(ethylene oxide)-lithium bis(trifluoromethanesulfonyl)imide-Li6.4La3Zr1.4Ta0.6O12/Y@CeO2 composite solid electrolyte (CSE) with significantly enhanced ionic conductivity (1.08 × 10−3 S cm−1 at 75 °C), mechanical strength, and electrochemical stability were fabricated using Y@CeO2 nanotubes with abundant oxygen vacancies. The LiFePO4/CSE/Li cell performed well in terms of capacity, rate performance, and cycle stability. At 60 °C, it afforded a discharge capacity of 168.7 mAh g−1 at 0.1 C-rate and 122.5 mAh g−1 at 1 C-rate. Remarkably, even after 100 cycles of 1 C-rate charge/discharge, the coin cell retained 99.3% of its original capacity. The use of inorganic-organic composite solid electrolytes in all-solid-state lithium metal batteries is encouraged by the composite filler design, which combines the benefits of active ceramic filler nanoparticles and inert ceramic filler nanotubes with ample oxygen vacancies.