Chemical substitution simultaneously constructing LiZn/LiCl composite protector to stabilize Li metal anode

Tremendous efforts have been made towards addressing the Li-dendrite issue for enhancing the practical applicability of Li metal batteries. However, challenges remain in exploring simple and efficient surface engineering for achieving uniform Li plating/stripping. Herein we report a one-step chemical substitution method (3Li + ZnCl2 = LiZn + 2LiCl) that simultaneously constructs a LiZn/LiCl surface layer onto metal Li. The obtained Li- LiZn/LiCl anode exhibits a coralline-like cross-linked surface structure, in which the LiZn alloy component is beneficial for uniform Li-ion deposition, while the LiCl component can prevent the electron transfer from inside Li to the surface layer, so that Li plating occurs between bulk Li and LiZn/LiCl layer, inhibiting the Li-dendrite formation. As a result, this anode enables promising electrochemical performance, and a representative LiNi0.8Co0.1Mn0.1O2//Li-LiZn/LiCl cell maintains 77% capacity retention (~ 185 mAh g^-1) after 300 cycles at 1.0 C rate. This study provides a straightforward and effective surface engineering for improving the anode of Li metal batteries.