Synthesis Of Nickel Silicides, Silicon, Germanium Nanostructures And Their Application In Li-ion Batteries

One-dimensional (1-D) nanomaterials, including nanowires, nanotubes, and nanorods have already been a worldwide research hot spot in the field of current nanotechnology due to their large ratio of length to diameter, high anisotropy, and unique structures and properties. The study on their synthesis, assembling, and nature is conducive to a deep understanding of crystal growth, effective control of morphologies and structures, and exploration of relationship between property and structure, which will lay a firm foundation for designing and fabricating nanoscale devices in the future. Now 1-D nanomaterials have been successfully applied in a large number of areas, such as microelectronics, thermoelectrics, Li-ion batteries, photovoltaic, and biosensor. In our paper, we focus on the synthesis of nickel silicide nanostructures to support Si and Ge as anode materials of Li-ion batteries.Nickel silicide nanostructures play an important role in the use for microelectronics, such as ohmic contact, interconnect, and gate contacts. We have employed chemical vapor deposition (CVD) method to synthesize nickel silicides nanostructures, whose morphologies and phases are successfully controlled by regulating the temperature and flow of SiH4. The nickel silicides nanostructures can be used to support Si and Ge as anode materials of the Li-ion batteries, which results in enhanced properties.Silicon, with the largest capacity, is the one of the most promising anode materials in the Li-ion batteries. Germanium is also attractive due to the very fast diffusion of Li+in Ge. In our experiment, we have adopted CVD and subsequent RF sputtering method to prepare Si nanowires, NisSi2-Si nanowires, Si/Ni3Si2 nanorod arrays, Ge/NiSix, all of which are used as anodes for Li-ion batteries. The optimized anodes show the enhanced properties due to the unique core-shell array structure that can provide good conductivity and alleviate the volume change during the charge-discharge process. Our novelty is based on the use of nickel silicides that bring the capacity enhancement and stabilization.