Reduced Graphene Oxide-Wrapped Novel CoInS Spinel Composite Anode Materials for Li-ion Batteries.

In this study, we proposed a novel CoInS/reduced graphene oxide (CoInS/rGO) composite anode using a hydrothermal method. By introducing electronic-conductive reduced graphene oxide (rGO) to buffer the extreme volume expansion of CoInS, we prevented its polysulfide dissolution during the lithiation/de-lithiation processes. After 100 cycles, the pristine CoInS electrode demonstrated poor cycle performance of only 120 mAh/g at a current density of 0.1 A/g. However, the composition-optimized CoInS/rGO composite anode demonstrated a reversible capacity of 580 mAh/g for 100 cycles, which was an improvement of 4.83 times. In addition, the ex situ XRD measurements of the CoInS/rGO electrode were conducted to determine the reaction mechanism and electrochemical behavior. These results suggest that the as-synthesized CoInS/rGO composite anode is a promising anode material for lithium ion batteries.