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

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 Li2 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, Li2 S-rich SEI, as well as the homogeneous Li+ flux. Full cells with LiFePO4 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.