Three-dimensional Laser-induced Hierarchical Copper Current Collector for High-performance Lithium Metal Batteries

Lithium metal, as the most ideal anode material for high energy density batteries, has high capacity and low electrochemical potential. However, the decrease in battery stability caused by the growth of Li dendrites during cycling, and the capacity drop caused by uneven Li plating both hinder the practical application of lithium metal as an anode material. Herein, we fabricate a copper current collector with 3D hierarchical structure by simple ultrafast laser processing method. The micron-scale groove structure can accommodate the volume change of lithium during the plating and stripping process, and reduce the local current density by increasing the specific surface area. Moreover, the laser-induced fluffy nano-Cu x O provides more nucleation sites for Li, which uniformizes Li plating and reduces the formation of Li dendrites. Compared with commercial copper foils, half-cells based on 3D hierarchical copper current collectors achieve high coulombic efficiencies over 90% after 125 cycles at 0.5 mA/cm2, and a symmetric cell has a long cycle life over 800 hours at 0.5 mA/cm ² . Therefore, our findings provide a feasible way to address the short-circuit problem and capacity decline caused by lithium dendrites in Li-ion batteries.