In situ synthesis of CoS2/RGO nanocomposites with enhanced electrode performance for lithium-ion batteries

This study reports a novel strategy of preparing CoS2/reduced graphene oxides (RGO) nanocomposites by employing graphene oxides (GO) as an oxidizing agent and Na2S2O3 as a reducing agent. CoS2 can be in situ synthesized with GO being reduced. X-ray diffraction (XRD), Raman spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical test are used to characterize the nanocomposite. The CoS2 particles with the size of 150 nm are dispersed in the networks made from thin RGO nanosheets. The CoS2/RGO nanocomposite as an anode material for lithium-ion batteries can deliver excellent reversible capacity retention (640 mA hg−1) after cycling 50 times when tested at 100 mA g−1 and rate performance. The enhanced electrochemical properties can be attributed to the nanoscale particles sizes of CoS2 in addition to the effects of RGO networks in preventing the agglomeration of CoS2 and absorbing lithium polysulfides during the charge-discharge processes.