Selective Lithium Deposition on 3D Porous Heterogeneous Lithiophilic Skeleton for Ultrastable Lithium Metal Anodes

Abstract Lithium (Li) metal batteries (LMBs) have been deemed as the next promising high‐energy battery systems for ultrahigh energy densities. However, serious Li dendrites and low Coulombic efficiency issues still impede the practical application of LMBs. Herein, a common three‐dimensional (3D) copper foam partially decorated by a thin lithiophilic tin (Sn) layer (CF@Sn) has been constructed as the current collector of a Li metal anode. The large Li ions prefer to be induced by a Sn layer to produce Li−Sn alloy and selectively deposit on the alloy layers of the composite matrix. Due to the excellent confinement of the growth of metallic Li, the 3D porous heterogeneous lithiophilic skeleton can effectively improve uniform Li deposition, inhibit Li dendrite formation, reduce electrolyte consumption and enhance the electrochemical performance. The composite matrix leads to a high Coulombic efficiency (98.5%) over 400 cycles and ultrastable Li charging/discharging behavior for 1000 h for the symmetric cell at 1 mA cm⁻². For the low energy barrier of alloy layer, small potential polarization (20 mV in symmetric cell) and nucleation overpotential (10.5 mV) can be obtained as expected. Especially, full cells paired with LiFePO₄ cathodes and CF@Sn@Li anodes deliver an enhanced rate capability and a great discharging capacity of 140 mAh g⁻¹ with high capacity retention of 95.2% after 300 cycles at 0.5 C. The proposed 3D lithiophilic skeleton demonstrates an effective strategy to realize stable and practical Li metal anodes.