Spinel rGO Wrapped CoV₂O₄ Nanocomposite as a Novel Anode Material for Sodium-Ion Batteries

Binary mixed transition-based metal oxides have some of the most potential as anode materials for rechargeable advanced battery systems due to their high theoretical capacity and tremendous electrochemical performance. Nonetheless, binary metal oxides still endure low electronic conductivity and huge volume expansion during the charge/discharge processes. In this study, we synthesized a reduced graphene oxide (rGO)-wrapped CoV₂O₄ material as the anode for sodium ion batteries. The X-ray diffraction analyses revealed pure-phased CoV₂O₄ (CVO) rGO-wrapped CoV₂O₄ (CVO/rGO) nanoparticles. The capacity retention of the CVO/rGO composite anode demonstrated 81.6% at the current density of 200 mA/g for more than 1000 cycles, which was better than that of the bare one of only 73.5% retention. The as-synthesized CVO/rGO exhibited remarkable cyclic stability and rate capability. The reaction mechanism of the CoV₂O₄ anode with sodium ions was firstly studied in terms of cyclic voltammetry (CV) and ex situ XRD analyses. These results articulated the manner of utilizing the graphene oxide-coated spinel-based novel anode-CoV₂O₄ as a potential anode for sodium ion batteries.