Preparation of Silicon Nanostructures for Lithium Ion Battery Anodes

One important challenge, among several others, in using silicon nanostructures as anodes in lithium ion batteries concerns finding cost effective fabrication routes for their connection to a suitable current collector. Here we present synthesis and characterization of silicon nanostructures by plasma enhanced chemical vapor deposition and template assisted electrodeposition on conducting substrates. The two methods give materials with different morphologies. Silicon nanowires were grown by chemical vapor deposition utilizing the gold catalyzed vapor-liquid-solid growth mechanism. A decrease in the nucleation time for silicon wire growth on stainless steel and aluminum substrates was observed with increasing growth temperature and SiH4 pressure. The utilization of plasma enhancement resulted in the formation of silicon thin films. Copper substrates, without diffusion barrier, were found to be unsuitable for gold catalyzed vapor-liquid-solid growth. Silicon films and dots were deposited on copper and copper/gold substrates by template assisted electrochemical deposition in ionic liquids.