In Situ Reconstruction of the Ceramic Particle Surface Boosting High-Performance and Ultrathin Hybrid Solid-State Electrolyte

Garnet-based solid electrolytes endow lithium-based batteries with higher safety and energy density as compared to those of conventional lithium-ion batteries. The dry process is a promising fabrication method to eliminate energy-intensive drying and solvent recovery steps, preventing degradation of garnet-based electrolytes during the production of garnet-based solid electrolytes. However, owing to the poor ion conduction of Li₂CO₃ formed on ceramic particles, garnet-based composite solid electrolytes synthesized by the dry processing method normally exhibit unsatisfactory ionic conductivity. Herein, we propose an interface-reconstructing strategy to in situ convert the insulating Li₂CO₃ into a lithium salt-rich layer, which is beneficial to further form a highly Li⁺ conductive eutectic bridge between ceramic particles. Based on the optimization, an ultrathin ceramic electrolyte membrane (20 μm) exhibits an excellent Li⁺ conductivity of 5.56 × 10^-4 S cm^-1 at 30 °C and high safety. After 500 cycles at a 1C rate, the capacity retention rate of the assembled quasi-solid-state lithium metal battery is 80.2%, much better than similar work reported previously. Taken together, this facile bridge strategy can effectively improve the electrochemical performance, which facilitates the mass production of ceramic electrolyte membranes.