In Situ Polymerization Inhibiting Electron Localization in Hybrid Electrolyte for Room‐Temperature Solid‐State Lithium Metal Batteries

Abstract Hybrid solid electrolytes (HSEs) have attracted much attention due to their advantages as both inorganic and organic polymer electrolytes. However, the organic/inorganic interfacial space charge layer has a great barrier to the transport of Li⁺ in the HSE. Here, an in situ polymerization layer is proposed on garnet‐type particles, working as the coherent region to eliminate the space charge layer at the organic/inorganic interfaces by inhibiting electron localization. The conjugate hybridization of fillers weakens the aggregation of particles, induces the dissociation of Li salt, and provides high‐throughput Li⁺ transport pathways at the ceramics/polymer interface. Furthermore, the continuous Li⁺ conduction networks are connected by the coherent region between inorganic fillers and polymer chains. The fabricated HSE exhibits a high ionic conductivity of 0.47 mS cm⁻¹ and ion migration numbers of 0.78 at room temperature. The 3D Li//Li systematic battery assembled with the HSE delivers a high critical current density (CCD) of 2.0 mA cm⁻². Meanwhile, the 4.5 V NCM811//Li batteries achieve a prolonged operation of 500 cycles at 0.5 C. The Li//LiFePO₄ batteries demonstrate superior capacity retention of 96.4% at 1 C after 500 cycles.