The facile synthesis of nickel silicide nanobelts and nanosheets and their application in electrochemical energy storage

摘要

Ni silicides in the form of nanobelts and nanosheets were synthesized for the first time based on the chemical reaction of Ni substrate with SiHCl3 under H-2 atmosphere at 900 degrees C. Their morphological, structural and compositional features were characterized in detail using scanning electron microscopy, transmission electron microscopy, electron diffraction, energy-dispersive x-ray spectroscopy and x-ray diffraction. It was found that the nanobelts, 120-180 nm in thickness and 1-5 mu m in width, comprise a single Ni3Si phase and the nanosheets 20-80 nm in thickness consist of Ni3Si and Ni31Si12, which is influenced by the concentration ratio of SiHCl3 to H2. Moreover, the potential application of these Ni silicides in electrochemical energy storage was also investigated. The results indicate that the nanosheets have excellent electrochemical performance when used as anode material for high energy density lithium ion batteries: a reversible capacity of more than 540 mA h g(-1) can be maintained even for the 20th cycle in a standard Li+ half-cell.