High-Performance Solid-State Lithium Metal Batteries of Garnet/Polymer Composite Thin-Film Electrolyte with Domain-Limited Ion Transport Pathways.

The integrated approach of interfacial engineering and composite electrolytes is crucial for the market application of Li metal batteries (LMBs). A 22 μm thin-film type polymer/LiLaZrTaO (LLZTO) composite solid-state electrolyte (LPCE) was designed that combines fast ion conduction and stable interfacial evolution, enhancing lithium metal interface stability and cycling performance. The ether-based molecular coordination groups/clusters formed by triethylene glycol dimethyl ether (TGDE) and anions facilitated the movement of Li between the polymer chain segments. These specific coordination clusters significantly "constrained" the interaction between anions and Li, inducing the anions to follow the clusters to the Li metal and preferentially participate in solid electrolyte interface (SEI) derivatization. The inorganic salt-rich gradient SEI modulates Li deposition and inhibits uncontrolled dendrite growth, achieving stable cycling of Li symmetric cell at 0.2 mA cm for over 2000 h. Furthermore, the Li||NCM811 cell at a rate of 0.1 C exhibits an initial discharge capacity of 194.5 mAh g, maintaining a capacity retention rate of over 90% after 500 cycles. This work demonstrates the importance of domain-limited ion clusters in ion transport and interfacial evolution, providing a perspective for solid-state LMBs.