Surfactant-assisted synthesis of a Co3O4/reduced graphene oxide composite as a superior anode material for Li-ion batteries

Abstract

A Co₃O₄/reduced graphene oxide (rGO) composite was prepared by a convenient PVP (polyvinylpyrrolidone)-assisted method under reflux conditions. The prepared composite material consists of uniform Co₃O₄ nanoparticles (NPs about 100 nm), which are tightly enwrapped by rGO in the presence of PVP. This has been confirmed through observations by field emission scanning electron microscopy and transmission electron microscopy. The Co₃O₄/rGO composite exhibits superior Li-battery performance with large reversible capacity, excellent cyclic performance, and good rate capability, which is higher than that of the previously reported pure rGO and Co₃O₄ NPs. The anode was able to deliver a discharge capacity of 860 mA h g⁻¹ during the 120^th cycle at 40 mA g⁻¹. The superior electrochemical performance of the Co₃O₄/rGO composite is attributed to its unique nanostructure, which closely combines the conductive graphene network with the uniformly dispersed Co₃O₄ NPs. X-ray absorption near-edge spectroscopy (XANES) was used to analyze the Co oxidation state of the Co₃O₄/rGO composite electrode.