Immobilizing Ceramic Electrolyte Particles into a Gel Matrix Formed In Situ for Stable Li-Metal Batteries

Hybrid solid/gel electrolytes (SGEs) have generated much research attentions because of their capability to suppress Li dendrite growth and improve battery safety. However, the interfacial compatibility of the electrode/electrolyte or polymer/inorganic ceramics within hybrid electrolytes remains challenging for practical applications. Herein, an SGE is fabricated by confining ceramic particles (Li7La3Zr2O12; LLZO) into in situ formed tetraethylene glycol dimethyl ether (G4)-based gel electrolytes within assembled cells. A hierarchical layered structure is formed when LLZO settles near the Li anode within the liquid electrolyte during the gradual gelatinization process. Good interfacial compatibility is obtained from good contact with the liquid G4 component. The LLZO layer also serves as an ionic sieve to redistribute the Li deposition. This SGE endows stable Li stripping/plating cycling over 800 h at 0.5 mA/cm2 (60 °C). Moreover, Li-metal batteries with an SGE coupled with LiFePO4 and an air cathode both exhibit superior cycling performance. This work presents a promising strategy for hierarchically layered SGEs for high-performance Li-metal batteries.