Hierarchical Cu fibers induced Li uniform nucleation for dendrite-free lithium metal anode

The hierarchical copper fibers grown vertically on the copper foam skeleton (HCF/CF) by a facile strategy. The Cu fibers with numerous protuberances secondary structure provide the electrochemical active sites, which sever as charge centers to induce Li uniform nucleation and deposition on HCF/CF skeleton. Furthermore, the abundant porous structures of HCF/CF current collector can alleviate the volume change during repeated Li plating/striping. [Display omitted] •Numerous protuberances act as charge centers to induce Li uniform deposition.•Increased specific surface area and porosity decrease the real current density.•The HCF/CF skeleton reveals a high Coulombic efficiency.•Li/Li symmetrical batteries show a long lifespan.•The preparation strategy of HCF/CF skeleton is feasible and facile. Li metal has been regarded as the most promising anode material for next-generation high-energy-density batteries. However, the growth of lithium dendrites caused by non-uniform deposition brings many obstacles to the commercialization process of metallic Li anodes. An effectively designed 3D current collector can significantly suppress the lithium dendrites growth and related issues. Herein, we develop a 3D conductive skeleton that hierarchical copper fibers grown vertically on the copper foam skeleton (HCF/CF) by a rational strategy. The Cu fiber with numerous protuberances secondary structure can provide the electrochemical active sites, which sever as charge centers to induce Li uniform nucleation and deposition on HCF/CF skeleton. Furthermore, the abundant porous structure of HCF/CF current collector can alleviate the volume change during repeated Li plating/striping. Comparison with Cu foam, the HCF/CF skeleton reveals an observably improved Li plating/striping behavior and a high Coulombic efficiency (98% retention after 200 cycles). The Li anode based on HCF/CF current collector can run for 820 h at a current density of 1 mA cm−2 without evident voltage fluctuation. The full cells of Li@HCF/CF|LFP exhibit a superior cycling and rate performance. The strategy for modifying foam copper has effectively improved the deposition behavior of lithium as well as enhanced the electrochemical performance of lithium anode.