A Silica‐Reinforced Composite Electrolyte with Greatly Enhanced Interfacial Lithium‐Ion Transfer Kinetics for High‐Performance Lithium Metal Batteries

Abstract Developing quasi‐solid‐state electrolytes with superior ionic conductivity and high mechanical strength is urgently desired to improve the safety and cycling stability of lithium‐metal batteries. Herein, a novel solid‐like electrolyte (SLE) with enhanced Li + interfacial transfer kinetics is rationally designed by soaking bulk nanostructured silica–polymer composites in liquid electrolytes. Benefiting from the high content of inorganic silica and abundant interfaces for fast Li + ‐transport channels, the prepared SLE exhibits superb ionic conductivity and high mechanical strength. Furthermore, fumed silica with a high specific area in the SLE can homogenize Li + flux and electrical field gradient. More importantly, a Li 2 S‐rich solid electrolyte interphase (SEI) is constructed on the lithium metal due to the intimate ion coordination in the SLE. Therefore, the lithium‐metal anode exhibits excellent electrochemical performance in symmetric Li–Li cells due to the merits of superior ionic conductivity, high modulus, Li 2 S‐rich SEI, as well as the homogeneous Li + flux. Full cells with LiFePO 4 cathode can still display a capacity retention of 98% at 0.2 C after 400 cycles. The proposed strategy on quasi‐solid‐state electrolytes provides a promising avenue for next‐generation metal‐based batteries.