AlF₃-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 AlF₃-decorated three-dimensional graphene aerogel (AlF₃/GA) as the host material for a composite lithium anode (AlF₃/GA/Li) via a thermal infusion method. The reaction between AlF₃ 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 AlF₃/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 AlF₃/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.