Homogeneous Interface Conductivity for Lithium Dendrite-Free Anode

Dendrite growth is one of the major problems that hinder the practical application of lithium metal electrodes in rechargeable lithium batteries. Herein, we report that the thin-film Cu3N coating can greatly suppress the lithium dendrite growth on the Cu current collector. Li|Cu and LiFePO4|Cu cells using thin-film Cu3N-modified Cu foil as electrode exhibit improved cyclic stability and low charge–discharge overpotential. A multifaceted investigation demonstrates that Cu3N can convert to Li3N/Cu nanocomposite after initial lithium plating, forming in situ a highly homogeneous conductive network. The peak-force tunneling atomic force microscopy experiments enable the direct measurement of the surface conductivity, confirming the improved distribution uniformity for the Cu3N-modified Cu. These findings suggest that the uniformity of surface electronic conductivity is an important factor for homogeneous lithium plating–stripping, and in situ formation of a nanoconductive network via conversion reaction could be an effective way to smoothen surface conductivity and thus to achieve high uniformity.