Mixed morphology ternary composites of ZnCo2O4/WS2/COOH-CNTs for high performance supercapacitor application

Transition metal oxides, dichalcogenides, and their composites with carbonaceous materials have proven good electrochemical properties for supercapacitor applications. In this study, we synthesized WS₂ nanosheets via liquid phase exfoliation. Mesoporous flower /urchin like ZnCo₂O₄, binary composites of ZnCo₂O₄/WS₂ and ZnCo₂O₄/FCNTs; and a ternary composite of ZnCo₂O₄/WS₂/FCNTs hydrothermally. The ternary composite showed a BET-specific surface area of 204.2 m²/g and an average BJH pore size of 3.456 nm. The shape of the CV curve of the ternary composite suggested a battery-like nature. Galvanostatic charge-discharge (GCD) was done at current densities of 0.5 A/g, 1 A/g, 2 A/g, and 5 A/g. The specific capacity of ZnCo₂O₄/WS₂/FCNTs, measured at a current density of 0.5 A/g is found to be 540.5 C/g. The highest energy density shown by the ZnCo₂O₄/WS₂/FCNTs device is 55 Whkg⁻¹ at a power density of 490 Wkg⁻¹. The cyclic stability of the two-electrode device shows a capacity retention of 87 % over 10000 cycles at 12 A/g. The electrochemical results suggested the ternary electrode ZnCo₂O₄/WS₂/FCNTs as a better electrode material for supercapacitor applications. The reason for better performance as compared to the other synthesized electrodes is the synergistic effect of the three constituents.