Facile synthesis of a copper oxide/molybdenum disulfide heterostructure for asymmetric supercapacitors of high specific energy

A unique p-n heterostructural CuO/MoS₂ composite is synthesized by a facile hydrothermal method. The active edge-sites of two-dimensional MoS₂ nanosheets provide ample surface area for firm attachment of urchin-shaped CuO particles without agglomeration during formation of the p-n heterostructure. The composition and morphology of the heterostructure are characterized by field-emission scanning electron microscopy, X-ray diffraction, Fourier - transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The synergism between CuO and MoS₂ enhances electrochemical performance by increasing the number of sites available for redox reactions. Electrochemical measurements establish a specific capacitance of 268 F/g and a cyclic stability of 90.02 % in an alkaline electrolyte solution. An asymmetric supercapacitor fabricated with a CuO/MoS₂ positive electrode and a biomass-derived activated carbon (BAC) negative electrode (CuO/MoS₂//BAC) achieved a specific energy of 26.66 W h/kg at a specific power of 1599.6 W/kg.