AlF 3 -Decorated 3D Graphene Aerogel as a Multifunctional Host Material for High-Performance Lithium Metal Anodes

To address the issues of infinite volume change, Li dendrite growth, and unstable solid electrolyte interphase (SEI) during the plating/stripping process of lithium metal anodes, we designed an AlF 3 -decorated three-dimensional graphene aerogel (AlF 3 /GA) as the host material for a composite lithium anode (AlF 3 /GA/Li) via a thermal infusion method. The reaction between AlF 3 and molten lithium produces a lithiophilic Li–Al alloy and LiF, contributing to the formation of a stable LiF-rich SEI layer. The lithiophilic Li–Al alloy reduces the nucleation overpotential of lithium metal. The LiF-rich SEI regulates the homogeneous deposition of Li + and inhibits lithium dendrite growth. The gradient porous structure of GA provides sufficient space to accommodate the volume change during the Li plating/stripping process. The as-prepared AlF 3 /GA/Li symmetric cell maintains an extremely low overpotential of 19 mV after 800 h of cycling at 2 mA cm –2 and 2 mAh cm –2 . The full cell assembled with the AlF 3 /GA/Li anode and a high-sulfur-loading sulfur cathode delivers an ultrahigh initial discharge specific energy of 836.62 Wh kg –1 based on the total mass of both the cathode and anode. This study provides an effective strategy for achieving high-energy-density and long-life lithium metal batteries through synergistic structural and interfacial optimization.