Inorganic Filler Enhanced Formation of Stable Inorganic-Rich Solid Electrolyte Interphase for High Performance Lithium Metal Batteries

Lithium metal (LM) is a promising anode material for next generation lithium ion based electrochemical energy storage devices. Critical issues of unstable solid electrolyte interphases (SEIs) and dendrite growth however still impede its practical applications. Herein, a composite gel polymer electrolyte (GPE), formed through in situ polymerization of pentaerythritol tetraacrylate with fumed silica fillers, is developed to achieve high performance lithium metal batteries (LMBs). As evidenced theoretically and experimentally, the presence of SiO2 not only accelerates Li+ transport but also regulates Li+ solvation sheath structures, thus facilitating fast kinetics and formation of stable LiF-rich interphase and achieving uniform Li depositions to suppress Li dendrite growth. The composite GPE-based Li||Cu half-cells and Li||Li symmetrical cells display high Coulombic efficiency (CE) of 90.3% after 450 cycles and maintain stability over 960 h at 3 mA cm(-2) and 3 mAh cm(-2), respectively. In addition, Li||LiFePO4 full-cells with a LM anode of limited Li supply of 4 mAh cm(-2) achieve capacity retention of 68.5% after 700 cycles at 0.5 C (1 C = 170 mA g(-1)). Especially, when further applied in anode-free LMBs, the carbon cloth||LiFePO4 full-cell exhibits excellent cycling stability with an average CE of 99.94% and capacity retention of 90.3% at the 160th cycle at 0.5 C.

Automated summary

A composite gel polymer electrolyte (GPE) is developed by in situ polymerization of pentaerythritol tetraacrylate with fumed silica fillers, leading to high performance lithium metal batteries (LMBs). The GPE contains SiO2, which enhances Li+ transport and regulates Li+ solvation sheath structures, resulting in fast kinetics and a stable LiF-rich interphase, thus suppressing Li dendrite growth. The GPE-based LMBs show high Coulombic efficiency and stability in different configurations.