Electrochemically Dealloyed 3D Porous Copper Nanostructure as Anode Current Collector of Li‐Metal Batteries

The commercialization of high-energy Li-metal batteries is impeded by Li dendrites formed during electrochemical cycling and the safety hazards it causes. Here, a novel porous copper current collector that can effectively mitigate the dendritic growth of Li is reported. This porous Cu foil is fabricated via a simple two-step electrochemical process, where Cu-Zn alloy is electrodeposited on commercial copper foil and then Zn is electrochemically dissolved to form a 3D porous structure of Cu. The 3D porous Cu layers on average have a thickness of ≈14 um and porosity of ≈72%. This current collector can effectively suppress Li dendrites in cells cycled with a high areal capacity of 10 mAh cm^-2 and under a high current density of 10 mA cm^-2 . This electrochemical fabrication method is facile and scalable for mass production. Results of advanced in situ synchrotron X-ray diffraction reveal the phase evolution of the electrochemical deposition and dealloying processes.