Reduced Graphene Oxide-Wrapped Novel CoIn₂S₄ Spinel Composite Anode Materials for Li-ion Batteries

In this study, we proposed a novel CoIn₂S₄/reduced graphene oxide (CoIn₂S₄/rGO) composite anode using a hydrothermal method. By introducing electronic-conductive reduced graphene oxide (rGO) to buffer the extreme volume expansion of CoIn₂S₄, we prevented its polysulfide dissolution during the lithiation/de-lithiation processes. After 100 cycles, the pristine CoIn₂S₄ electrode demonstrated poor cycle performance of only 120 mAh/g at a current density of 0.1 A/g. However, the composition-optimized CoIn₂S₄/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 CoIn₂S₄/rGO electrode were conducted to determine the reaction mechanism and electrochemical behavior. These results suggest that the as-synthesized CoIn₂S₄/rGO composite anode is a promising anode material for lithium ion batteries.