Abstract:
In spite of its excellent discharge capacity, low conductivity and poor cycling stability prevent to commercialize silicon negative electrodes for the Lithium ion batteries (LIBs). Since graphene has large surface area, high electrical conductivity and discharge capacity, silicon/graphene nanocomposite anodes in proper architectures alleviate difficulties to improve electrochemical performances of the LIBs. This article demonstrates the nanocomposite synthesizing with 10 wt.%, 30 wt.% and 50 wt.% graphene oxide (GO) dispersion in the silicon matrix following reduction of GO (rGO) result in remarkable improvements in the discharge capacity, cycle stability and rate capability. Mechanical milling after GO reduction provides decoration of silicon nanoparticles between the rGO sheets and improves interfacial bonding between silicon and rGO which alleviates huge volume increase during cycling. Among the nanocomposite negative electrodes, 50 wt.% rGO exhibits highest reversible capacity of about 2000 mAh g(-1) after 100 cycles and good coulombic efficiency approximately 99%. This study proves that dispersion of silicon with rGO and the increase content of rGO lead to improve ionic conductivity, cycling stability, reversibility and rate capability of the Lithium ion cell. Because of the easy scaling-up possibility of the method Si/rGO hybrid nanocomposites can be new electrodes for electrochemical energy storage. (C) 2016 Elsevier Ltd. All rights reserved.
