Three-dimensional nickel-silicide foam loaded with dense silicon nanowires as a robust anode for lithium-ion batteries

Silicon, with its many advantages, is gaining attention in the field of lithium-ion battery anode materials. However, severe volume swelling, poor conductivity, and slow Li+ diffusion kinetics are major obstacles to enhancing the electrochemical properties of silicon anodes. One-dimensional silicon nanowires with a high aspect ratio can effectively ameliorate these issues, while the complexity of the synthesis method limits its development. Here, a three-dimensional flexible electrode of binary-phase Ni-silicide foam loaded with silicon nanowires (NixSiy@Si NWs) was constructed in two simple steps: preparation of metal catalyst nanoparticles using a chemical plating approach and production of silicon nanowires by the supercritical fluid-liquid-solid mechanism. Benefiting from the excellent anchoring ability and superior electrical conductivity of NixSiy as well as the extra space and favorable Li+ and electrolyte diffusion paths provided by the Si NWs network, the as-obtained anode exhibits a high initial Coulombic efficiency of 77% at 0.5 A g-1, excellent cycling performance (a reversible capacity of 1238 mAh g(-1) after 200 cycles) and outstanding rate capability (2675, 2497, 2164, 1740, and 1222 mAh g(-1) at 0.5, 1, 2, 4, and 8 A g(-1), respectively).