Lithium metal deposition under the geometrical confinement effect: Dendritic copper foam current collector

Dendrite-free lithium is the ultimate goal in achieving the commercial application of lithium metal anode. In this paper, Dendritic Copper Foam Current Collector (DCFC) is prepared by an electrometallurgy method to realize the homogeneous deposition of lithium metal. The deposition behavior of Cu and Li on different interfaces was studied. Firstly, the Cu dendrites constructed on the surface of Cu foam are induced and formed by the potential oscillation generated by the hydrogen evolution reaction. Secondly, the heterogeneous nucleation model reveals that the reason for the dendrite-free lithium deposition on the dendritic copper foam is the geometrical confinement effect. Compared with commercial copper foam, DCFC with hierarchical structure significantly reduces the nucleation energy and deposition overpotential of lithium metal. The in situ optical microscope observation and finite element simulation results confirm our ideas. Electrochemically, DCFC works stably after 1200 h at a lower potential of 36 mV in a DCFC@Li symmetric battery, which is much superior to 75 mV for just 340 h in Cu foam. The ideal collector with a dendritic structure has broad prospects for the practical application of lithium metal anode.