Constructing Gradient Lithiophilic Structure within 3D Stable Framework for Dendrite-Free Lithium Metal Anode

Abstract

This study proposes a gradient lithiophilic structure (CuO-Ag@NF) constructed on nickel foam (NF) to achieve dendrite-free lithium metal anodes. The framework was fabricated through replacement reaction-deposited nano-silver (Ag@NF), electrochemically deposited copper layer (Cu-Ag@NF), followed by calcining to yield CuO-Ag@NF. Density functional theory calculations demonstrate that the gradient architecture of CuO-Ag@NF significantly enhances lithium adsorption energy (-4.26 eV) relative to single-component systems (CuO@NF: -3.72 eV; Ag@NF: -2.46 eV), concurrently homogenizing electric field distribution and reducing nucleation overpotential to 36.5 mV. Electrochemical validation confirms exceptional performance, with half-cells achieving 450 cycles at 1 mA cm-2/1 mAh cm-2 (99.5% Coulombic efficiency), symmetric cells maintaining stable operation for 1,650 h at 1 mA cm-2/1 mAh cm-2 (15 mV polarization), and LiFePO4 full cells retaining 95.3% capacity after 400 cycles at 1 C. Structural characterization reveals that the gradient structure promotes uniform deep lithium deposition while suppressing the formation of dendrites and dead Li. This work provides a viable strategy toward high-safety, long-life lithium metal batteries.