Article ID Journal Published Year Pages File Type
1286184 Journal of Power Sources 2007 9 Pages PDF
Abstract

Nanocomposites comprising silicon (Si), graphite (C) and single-walled carbon nanotubes (SWNTs), denoted as Si/C/SWNTs, have been synthesized by dispersing SWNTs via high power ultrasonication into a pre-milled Si/C composite mixture, followed by subsequent thermal treatment. The Si/C composite powder was prepared by high-energy mechanical milling (HEMM) of elemental Si and graphite using polymethacrylonitrile (PMAN) as a diffusion barrier suppressing the possible mechanochemical reaction between silicon and graphite to form SiC, and further prevent the amorphization of graphite during extended milling. A nanocomposite with nominal composition of Si-35 wt.% SWNTs-37 wt.% exhibits a reversible discharge capacity of ∼900 mAh g−1 with an excellent capacity retention of capacity loss of 0.3% per cycle up to 30 cycles. Functionalization of the SWNTs with LiOH significantly improves the cyclability of the nanocomposite containing Si-45 wt.% SWNTs-28 wt.% exhibiting a reversible capacity of 1066 mAh g−1 and displaying almost no fade in capacity up to 30 cycles. The improved electrochemical performance is hypothesized to be attributed to the formation of a nanoscale conductive network by the dispersed SWNTs which leads to successful maintenance of good electrical contact between the electrochemically active particles during cycling.

Related Topics
Physical Sciences and Engineering Chemistry Electrochemistry
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