Lithiophilic coating layer modify three-dimensional Cu foam for stable and dendrite-free lithium metal anode

Abstract

The widespread research for lithium metal anodes (LMA) has been rapidly developed in recent years. However, undesirable dendritic structures generated in the process of unstable lithium (Li) deposition dramatically restricts the cycle life of LMA. The skeleton structure of the three-dimensional (3D) host substrates are the potential promising host for Li, which can alleviate volume expansion during cycling. Herein, we propose a facile surface modification approach through ion sputtering, which can effectively regulate the lithiophilic properties of Cu foam (CF) for facilitating Li deposition. Au modified surface can enhance the lithiophilic property of substrates and induce uniform Li deposition along the conductive skeleton. Further analysis of results, substrate with Au coating modified surface exhibits a smaller Li nucleation overpotential (12 mV), a more stable coulombic efficiency (CE) at different current densities, and more uniform morphology of Li deposition with dendrite-free at large capacity of 4 mAh cm-2. Meanwhile, symmetric cells with Au coating on CF can stably operate more lifespan than other samples. Furthermore, full cells paired with LiFePO4 cathodes and CF coated Au exhibit remarkable discharge capacities and capacity retention than others. This work provides new insights toward developing excellent 3D skeleton with modified surface for dendrite-free LMA.