关键词: 锂金属电极, 锂金属电极, 三维多孔集流体, 铋修饰层, 无锂枝晶

Abstract: In this work, 3D Cu@Bi was constructed by electrodepositing a bismuth modification layer on the surface of 3D porous copper with micrometer-sized pores prepared by an electroless plating, and served as the current collector to improve the electrochemical performance of Li metal electrode. The 3D porous structure with a pore diameter of about 5 μm has a high surface area, which reduces the local current density and results in uniform current density distribution, and its large free space can alleviate the volume change, release the stress and inhibit the growth of lithium dendrites. In addition, under the assistance of high lithophilicity of Bi modified layer, the 3D Cu@Bi decreases the nucleation overpotential of Li, and enhances the reversibility of lithium plating/stripping. Under the synergistic effects of three-dimensional porous structure and Bi modified layer, the electrode surface remains flat and smooth even when the lithium metal deposition capacity is more than 4 mAh cm-2; The half cells can be stably cycled for more than 200 cycles and the Coulomb efficiency (CE) can be maintained above 98.5%; the symmetrical cell Li||3D Cu@Bi@Li stably cycle for above 1500 h at high current density of 0.5 mA cm-2 with a capacity of 1 mAh cm-2, and the electrode surface is still smooth and free of dendrites after 100 cycles; the full cell LFP||3D Cu@Bi@Li with LiFePO4 as the cathode shows a high capacity of 132 mAh g-1 and a capacity retention rate of ≈87.2% after 200 cycles at 1 C.

Key words: Li metal batteries, Li metal electrode, 3D porous current collector, Bi modified layer, Li dendrite-free