Dendrite-free Na metal plating/stripping onto 3D porous Cu hosts

Metallic sodium (Na) has been generally regarded as one of the most promising anode materials due to its high specific capacity and natural abundance. However, uneven deposition, large volume change, and dendrite growth during Na plating/stripping process severely restrict its feasibility for energy storage devices. Here we propose a copper nanowire-reinforced three-dimensional (3D) Cu foam current collector (CuNW-Cu) to achieve highly reversible Na storage. The in-situ growth of Cu nanowires can provide abundant active nucleation sites and reduce the local electric current by increasing surface area of the current collector, leading to homogeneous Na deposition. The Na metal anode can run for more than 1400 h (350 cycles) on CuNW-Cu with a low thickness variation of 2% and a stable voltage hysteresis of 25 mV. Moreover, controllable Na loading ranging from 2 to 12 mA h cm−2 can be plated into CuNW-Cu with a long steady life-span over 1000 h and a high Coulombic efficiency over 97.5% owing to the synergistic effect between copper nanowires and interconnected 3D porous Cu foam, which delivers an excellent compatibility for cathodes with different areal loadings. Our results indicate that this hierarchically nanostructured current collector holds great potential for next-generation Na-based batteries.