Synthesis of nanosized Si particles via a mechanochemical solid-liquid reaction and application in Li-ion batteries

Nanosized silicon particles were obtained by reaction between SiBr4 solution and Mg granules during a ball-milling process. X-ray diffraction measurements show that crystallized silicon was obtained after 20 h of milling, together with MgBr2, non-reacted Mg and probably SiOx. The powder was subjected to a suitable cleaning treatment in order to minimize the proportion of residual products. The different analyses carried out after the treatment showed that the obtained silicon powder consists of nanosized Si particles with a limited oxidized fraction in regard to its high surface area. This material was considered for its application as the negative electrode for lithium-ion batteries. It delivers a large initial reversible capacity (1375 mAh g(-1)). The capacity turns out to be almost stable after the fifth cycle, reaching around 900 mAh g(-1), which is approximately twice that obtained with an electrode made from commercial 100 nm Si particles. (C) 2007 Elsevier B.V All rights reserved.