Three-dimensional ordered macroporous Cu current collector for lithium metal anode: Uniform nucleation by seed crystal

摘要

Lithium metal anode is regarded as the "holy grail' due to its extremely high specific capacity, low density and low reduction potential. However, Li dendrite growth reduces coulombic efficiency and causes safety accidents synchronously. In this paper, a rational designed three-dimensional ordered macroporous Cu is used as current collector for Li metal anode with excellent electrochemical performance, which is prepared by colloidal template method combined with copper electrodeposition. The novel porous Cu/Li anode with the pore size of 450 nm can stably run for 750 h at 0.2 mA/cm(2) with a small Li electroplating/stripping overpotential ( 30 mV), and it exhibits a high coulombic efficiency of 93.3% over 120 cycles. The three-dimensional ordered macroporous structure with large specific surface area results in lower local current density and enhances electrochemical reaction kinetics, and benefits Li deposition inside pores. Especially, the Li layer on the arc area of outer pores acts as seed crystal for the subsequent Li deposition, which leads to Li uniform nucleation and dendrite suppression effectively.