A Copper Silicide Nanofoam Current Collector for Directly Grown Si Nanowire Networks and their Application as Lithium-Ion Anodes

Silicon nanowires (Si NWs) have been identified as an excellent candidate material for the replacement of graphite in anodes, allowing for a significant boost in the capacity of lithium-ion batteries (LIBs). Herein, high-density Si NWs are grown on a novel 3D interconnected network of binary-phase Cu-silicide nanofoam (3D Cu_xSi_y NF) substrate. The nanofoam facilitates the uniform distribution of well-segregated and small-sized catalyst seeds, leading to high-density/single-phase Si NW growth with an areal-loading in excess of 1.0 mg cm⁻² and a stable areal capacity of ≈2.0 mAh cm⁻² after 550 cycles. The use of the 3D Cu_xSi_y NF as a substrate is further extended for Al, Bi, Cu, In, Mn, Ni, Sb, Sn, and Zn mediated Si NW growth, demonstrating the general applicability of the anode architecture.