Synergistic effect of LixSi/Li₃N artificial interface and 3D framework for enabling Dendrite-free, long-life lithium...

Lithium metal is highly favored as an ideal anode material in future high-capacity lithium batteries due to its appealing properties. Nevertheless, the implementation of lithium metal batteries (LMBs) is severely plagued by challenges such as instable solid electrolyte interface (SEI), uncontrolled growth of dendrite, and severe volume expansion. Herein, to address the aforementioned issues, an artificial SEI layer is fabricated, which is comprised of LixSi alloy and Li₃N. The in-situ generated LixSi/Li₃N interface is formed on the carbon fiber (denoted as CF/LixSi/Li₃N) through a spontaneous reaction between molten Li and Si₃N₄. Density functional theory (DFT) calculations reveal that LixSi alloy has low ion diffusion energy barrier, which facilitates the low nucleation overpotential of Li⁺ and enables homogeneous lithium deposition. Li₃N can further promote the rapid Li⁺ transport due to the excellent Li⁺ conductivity. In addition, the reserved 3D space effectively mitigates the volume change along cycling procedure. Owing to the synergistic effect of the LixSi/Li₃N protective layer and the 3D structure, the composite anode shows higher cycling stability with a lifetime of more than 3000 cycles at 1 mA cm^-2. Furthermore, matched with commercial LiFePO₄ (LFP) and LiNi₅Co₂Mn₃O₂ (NCM523) cathodes, the full cells also exhibit impressive electrochemical properties. This work introduces an ingenious approach for constructing stable lithium metal anodes and effective lithium metal batteries.