Effect of the Annealing Temperature of Lithiophilic Ag–Cu Co-Deposition on the Cycling Performance of Li-Metal Anodes

Abstract

Practical applications of Li-metal anodes are limited by dendrite formation, Li loss, and poor reaction, resulting in a low Coulombic efficiency. In this study, we investigated the effects of island-shaped Ag atoms on the electrochemical behavior of Li-metal anodes. A Ag–Cu film was co-deposited through sputtering and subsequent annealing to anchor the Ag atoms with an island shape on a Cu substrate. The Ag target was co-sputtered with Cu with controlled atomic ratios in the Ag–Cu alloy. The sputtering thickness was set to 100 nm, and various annealing conditions were applied. The embedded island-shaped Ag atoms provided effective nucleation sites for Li deposition during the electrochemical nucleation of Li, increasing the nucleation density and spatial uniformity while decreasing the nucleation size and potential. Compact dendrite-free high-density Li deposition was achieved by annealing the Ag–Cu current collector (CC) at 600 °C. Under repetitive Li plating and stripping for 110 cycles at a current density of 0.5 mAcm−2 and capacity of 1 mAhcm−2, a high Coulombic efficiency of 98.5% was achieved. Conversely, the bare Cu CC had a life of up to 67 cycles under the same test conditions.