Upgrading Traditional Organic Electrolytes toward Future Lithium Metal Batteries: A Hierarchical Nano-SiO2-Supported Gel Polymer Electrolyte

Developing safe and high-energy-density lithium metal batteries (LMBs) is considered to be the focus of next-generation rechargeable batteries. However, the inevitable lithium reaction with the liquid electrolyte and the subsequent formation of Li dendrites must be overcome, and upgrading traditional liquid electrolytes is a key strategy for achieving this goal. Here, we report a nano-SiO2-supported gel polymer electrolyte (SiO2-GPE) with a hierarchical structure fabricated via in situ gelation of a traditional organic liquid electrolyte supported on a functionally modified SiO2 layer, which displayed high ionic conductivity (1.98 × 10–3 S cm–1 at 25 °C) and wide electrochemical window (>4.9 V vs Li/Li+). The LiFePO4/SiO2-GPE/Li cells exhibited a high capacity of 125.5 mAh g–1 at 1 C with capacity retention of 88.42% after 700 cycles. The superior electrochemical performance is mainly due to the highly compatible electrode/electrolyte interface and the effective inhibition of Li dendrite growth provided by the synergistic effects of this SiO2-GPE membrane.