Alkaliphilic Cu(OH)2 Nanowires on Copper Foam for Dendrite-Free Alkali Metal Anodes

Abstract The uncontrollable dendritic behavior and volume expansion in alkali metal anodes have led to short-circuit issues and low Coulombic efficiency which significantly hamper the commercialization of alkali metal anodes. To address these issues, we report the fabrication of a novel functional host in which the alkaliphilic Cu(OH)2 nanowires were uniformly grown on Cu foam (denoted as Cu(OH)2-NWs@CF) for Li/Na anodes. The 3D network structure of Cu(OH)2-NWs@CF with high specific surface area can not only effectively reduce local current density to guide homogeneous deposition of Li+, leading to more controllable nucleation sites and dendrite-free Li deposition, but also minimize the volumetric strain during repeated Li/Na stripping/plating processes, mitigating the volume change of the batteries. Benefitting from these advantages, the as-prepared Li/Na@CF composite anodes exhibit outstanding long-term cycle stability and structure maintaining ability. In particular, the Li@CF-based symmetric cells deliver elevated cycling performance under a moderate polarization voltage for nearly 1200 hours at a current density of 1 mA cm-2. Similarly, the Na@CF-based symmetric cells can also cycle stably for 800 hours at a current density of 0.5 mA cm-2. Furthermore, the Li@CF||LFP full cells show significantly improved rate capability and high cycle stability (97% capacity retention after 100 cycles). Our work demonstrates the effectiveness of the 3D copper foam framework with improved alkaliphilic ability for the development of safe and commercially viable alkali metal anodes.