Preparation Of Novel Si-containing Nanomaterials By DC Arc Discharge And Their Characterizations

Silicon/graphene nanocomposites(Si/GNCs) are one of the promising candidates for the increasing demands of portable electronic devices and electric vehicle applications. Silicon/carbon(Si/C) core-shell nanowires or nanorods have emerged as the very interesting materials because the carbon shell protect the Si core from the formation of a thick insulating layer and photo-corrosion as well as providing conductive skin and additionally mechanical protection to the Si core.In this thesis, novel Si-containing nanomaterials, including Si/nitrogen-doped graphene composite nanosheets(Si/NDGCNSs), Si/C core-shell nanorods and nanoparticles were prepared by DC arc discharge method. The anodes were prepared by the compacting or filling methods with a certain mass ratio of Si dioxide(Si O2) and graphite or Si O2 and polyaniline(PAN) as the raw materials. The products were characterized by using SEM, TEM, HRTEM, EDX, EELS, XRD, Raman spectroscope, TG-DSC and UV-vis spectrometer. The effects of the Si O2 and carbon ratios, carbon source and methods of preparing anode on the morphology, structure and compositions of the products were investigated. The stabilities of the suspensions of the Si/NDGCNSs in distilled water and ethanol and their optical properties were also investigated. The possible formation and growth mechanisms of the Si/NDGCNSs and Si/C core-shell nanorods were discussed briefly.The results show that(1) the Si O2 and carbon ratio has remarkable influence on the morphologies and components of the products. When the ratio was 9:1(Si O2:graphite=19:1), the content of the nanorods in the product B1 was increased obviously, but the content of the nanosheets in the product C1 was decreased sharply;(2) the carbon source also has obvious influence on the morphologies and components of the products. When PAN was used as carbon source, the content of the nanorods in the product BP was also increased obviously, but the content of the nanosheets in the product CP was also decreased sharply;(3) the suspensions of the Si/NDGCNSs in distilled water and ethanol were stable for more than one and two month respectively, and both of them emitted green luminescence under the irradiation of UV light;(4) the compressing method is much better than the filling one.