Vacuum distillation derived 3D porous current collector for stable lithium–metal batteries

Lithium metal has been considered as the most ideal anode in lithium based batteries due to its high specific theoretical capacity and lowest working potential. Nevertheless, the growth of dendritic or mossy Li, the crush of solid electrolyte interface (SEI) layer and the successive reactions between the fresh Li metal and electrolytes hinder the commercialization of Li metal anode. In this paper, we utilize an environmental–friendly and low–cost one–step facile vacuum distillation approach to fabricate the 3D porous Cu current collector from commercial brass foil (Cu–Zn alloy) for Li metal anodes. The continuous porous 3D Cu skeleton is obtained after the vacuum distillated the low boiling point Zn (907 °C) component. The voids of the 3D porous copper can be easily regulated by adjusting the distillation temperature and time. As a current collector, the as–prepared 3D porous copper can inhibit the growth of Li dendrite and mitigate the huge volume change of Li metal anode during cycling process, resulting in stable SEI layer and electrode structure. As a result, the 3D porous Cu current collector can achieve a steady Coulumbic efficiency after 120 cycles at 0.52 mA cm⁻² and for more than 80 cycles at 1.04 mA cm⁻² with much reduced polarization. A long lifespan of 800 h is attained in the symmetric Li|Li@Cu battery, and it also indicates the potential for practical application when the Li@Cu|Li(NiCoMn)O₂ full battery is built. More promisingly, such a vacuum distillation method is plain and simple to be combined with current commercial technique of Li metal anode manufacture using a Cu current collector, exhibiting great potentials to accelerate the commercialization lithium metal based (such as Lithium–sulfur and Lithium–air) batteries and the development of high–energy lithium–ion batteries.