Cobalt-Phosphide-Modified Carbon-Coated Copper Current Collector for Stable Lithium Metal Deposition via Dendrite Suppression and Enhanced Ion Diffusion

In this study, a phosphide-functionalized interfacial layer was constructed on a 3D carbon-coated Co-modified copper current collector (Cu@C–Co) via a vapor-phase deposition technique, yielding a multifunctional Cu@C–Co–P architecture. This rational design synergistically integrates the high specific surface area of the hierarchical porous structure with the strong lithiophilicity of Cu3P, significantly reducing the lithium nucleation overpotential and enabling spatially confined lithium deposition within the 3D conductive framework. During cycling, an in situ-formed Li3P interphase with excellent ionic conductivity and mechanical robustness effectively suppresses dendritic growth and interfacial side reactions. Electrochemical evaluations demonstrate that the symmetric cells based on Cu@C–Co–P exhibit ultrastable cycling over 2600 h at 1 mA cm–2, while full cells maintain ∼90% capacity retention after 160 cycles at a high rate of 5 C. Moreover, the lithium-ion diffusion coefficient is enhanced by more than 28%. This work provides a multifunctional current collector design that simultaneously enables guided lithium deposition, interfacial stabilization, and fast ion transport, offering a promising pathway toward high-energy-density lithium metal batteries.