Nanocomposites and nanomaterials

Structure of silicon nano- and microparticles obtained by electric-spark dispersion method
Sergiienko R.A.1, Ilkiv B.I.2, Petrovska S.S.2, Lopatko K.G.3, Lopatko S.K.3, Vinarchuk K.V.3, Verkhovliuk A.M.1, Zaulychnyy Ya.V.4 
1 Physico-Technological Institute of Metals and Alloys of the NAS of Ukraine, 34/1, Vernadsky Ave., Kyiv, 03142, Ukraine, e-mail: rsruslan17@gmail.com.
2 Frantsevich Institute for Problems of Materials Sciences of the NAS of Ukraine, 3, Krzhyzhanovsky Str., Kyiv, 03142, Ukraine.
3 National University of Life and Environmental Sciences of Ukraine, Heroyiv Oborony st., 15, Kyiv-03041, Ukraine.
E-mail: date01092015@ukr.net
4 National Technical University of Ukraine “Kyiv Polytechnic Institute”, Engineering-physical Faculty, 35 Polytekchnichna Str., Kyiv 03056, Ukraine.

Silicon have been attracting a lot of attention lately as they demonstrate important properties for their technological application as a deoxidizer in steelmaking, alloy manufacturing, in the semiconductor industry, as electrode material for lithium-ion batteries, in optoelectronic devices, etc. [1,2].
Among the methods for the synthesis of small-size particles, the electric-spark dispersion (ESD) of granules in a liquid medium is a promising method because it combines temperature-deformation processing in the process of particle formation with high process technological effectiveness. In this study we synthesized silicon nano- and microparticles by electric-spark dispersion method in liquid methanol. Structure of silicon particles was studied by ultrasoft X-ray emission spectroscopy (USXES), x-ray photoelectron spectroscopy (XPS), X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was found that the synthesized silicon particles are polycrystalline with a wide size distribution ranging from a few nanometers to a few microns in diameter. USXES, XPS studies and TEM mapping analysis showed a high degree of oxidation of the surface of silicon particles and the presence on the surface of nanoparticles of oxygen-containing complexes with different charges of oxygen ions. While the core of the particles, according to electron and X-ray diffraction, consists of crystalline silicon with a cubic face-centered lattice. Some silicon nanoparticles had cores with amorphous structure. One measured the Li storage capacity of the synthesized silicon particles, by using three-electrode system.   
1.	Kwon H. J., Hwang J.-Y., Shin H.-J., Jeong M.-G., Chung K.Y., Sun Y.-K., Jung H.-G. Nano/Microstructured silicon–carbon hybrid composite particles fabricated with corn starch biowaste as anode materials for Li-ion batteries // Nano Lett. -2020, № 1.-20.-P. 625−635.
2.	Wang J., Huang W., Kim Y. S., Jeong Y. K., Kim S. C., Heo J., Lee H. K., Liu B., Nah J., Cui Y. Scalable synthesis of nanoporous silicon microparticles for highly cyclable lithium-ion batteries// Nano Research -2020.-13, № 6.-P. 1558-1563.