Preparation of MoFs-Derived Cobalt Oxide/Carbon Nanotubes Composites for High-Performance Asymmetric Supercapacitor

Metal-organic frameworks (MOFs)-derived metallic oxide compounds exhibit a tunable structure and intriguing activity and have received intensive investigation in recent years. Herein, this work reports metal-organic frameworks (MOFs)-derived cobalt oxide/carbon nanotubes (MWCNTx@Co₃O₄) composites by calcining the MWCNTx@ZIF-67 precursor in one step. The morphology and structure of the composite were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM) characterization. The compositions and valence states of the compounds were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Benefiting from the structurally stable MOFs-derived porous cobalt oxide frameworks and the homogeneous conductive carbon nanotubes, the synthesized MWCNTx@Co₃O₄ composites display a maximum specific capacitance of 206.89 F·g^-1 at 1.0 A·g^-1. In addition, the specific capacitance of the MWCNT₃@Co₃O₄//activated carbon (AC) asymmetric capacitor reaches 50 F·g^-1, and has an excellent electrochemical performance. These results suggest that the MWCNTx@Co₃O₄ composites can be a potential candidate for electrochemical energy storage devices.