Characteristics of layered polysilane and its application to lithium ion battery anodes

Abstract

Although layered polysilane (LPS) has a graphitelike structure and a higher electric capacity than Si powder, LPS shows poor cycling performance. Therefore, to improve its cyclability, the synthesis of composite materials of LPS and carbon was attempted. Carbon-coated LPS (C-LPS) was prepared by pulsed laser deposition (PLD), and a silicon–carbon (Si–C) composite consisting of silicon plates coated onto carbon particles was obtained by reacting LPS with sucrose. The cycling performance characteristics of the C-LPS and Si–C composite electrodes were better than that of the LPS electrode. On galvanostatic discharge–charge curves, although the Si–C composite showed no plateau at 0.3 V on the first discharge, the LPS and C-LPS electrodes showed a 0.3 V plateau that was due to the dissociation of the Si–H bonds of LPS, which led to a high initial irreversible capacity.