title: Dependence of milling time on electrochemical properties of nano Si electrodes prepared by ball-milling.
abstract: Morphology, crystallinity and electrochemical properties of Si powders fabricated by a mechanical milling process with milling time of 6-40 h were investigated by means of FESEM, XRD, Raman, TEM and cell test. Average size of Si powders was reduced to sub-micrometer scale after 10 h-milling and 40 nm-Si powders could be obtained at 48 h-milling. With increasing milling time, Si powders mostly changes from crystalline Si to amorphous one and the content of amorphous Si was increased. TEM result showed that a negligiable amount of crystalline Si remained even after 48 h-milling. Si electrode with 48 h-milled Si powders exhibited the best electrochemical properties in terms of capacity, efficiency and cycle performance: initial capacity of 3025 mAh g(-1), coulrombic efficiency of 79.4% and the capacity retention of 1000 mAh g(-1) (at 130 cycles). The good electrochemical properties of nano- and amorphous-Si are due to the high resistance against volume change and good reversibility of Li ion.
authors: School of Materials Science and Engineering and ERI, Gyeongsang National University, Gazwadong 900, Jinju, Gyeongnam 660-701, Korea.
authors: G B
authors: GB
authors: Cho
authors: S Y
authors: SY
authors: Choi
authors: J P
authors: JP
authors: Noh
authors: Y M
authors: YM
authors: Jeon
authors: K T
authors: KT
authors: Jung
authors: T H
authors: TH
authors: Nam