3D hierarchical Cu@Ag nanostructure as a current collector for dendrite-free lithium metal anode.

Abstract

Lithium metal is considered to be the best candidate for rechargeable batteries due to its unique advantages. But the instability and the uncontrollable dendrites of the lithium metal anode greatly limit its commercialization. In recent years, in order to obtain stable Li metal anodes, various three-dimensional (3D) current collectors have been proposed. However, for traditional 3D current collectors, its advantages in structure still need to be improved. Therefore, the 3D hierarchical Cu@Ag nanostructure consisting of Ag-decorated Cu nanowires grown on Cu foam as a current collector (denoted as 3D HCu@Ag) is well designed and successfully prepared. Cu nanowires were in situ grown on Cu foam to form a 3D hierarchical current collector to further increase the specific surface area and reduce the local current density, thus suppressing the formation of dendrites. Ag nanoparticles were in situ grown on the surface of Cu nanowires by displacement reaction, which can reduce the overpotential of lithium deposition. Under the synergistic effect of optimal structure and Ag surface modification, 3D HCu@Ag exhibits extremely excellent performance. As a result, the Li-3D HCu@Ag symmetrical cell exhibits a lifetime of 1500 h with a very low voltage hysteresis. More importantly, in practical application, the Li-3D HCu@Ag||LFP full cell can cycle stably for 200 cycles at 1C and maintain an extremely high-capacity retention rate of 78.5%. The experiment results show that this design provides a new idea for the lithiophilic 3D current collector for stable lithium metal anode.