Synthesis of hybrid ZIF-derived binary ZnS/CoS composite as high areal-capacitance supercapacitor

Abstract

Bimetal sulfide nanoparticle synthesized via a facile hydrothermal method using hybrid zeolitic imidazolate framework (ZIF-Co.Zn) and the made composites were analyzed using Field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Brunauer, Emmett, and Teller (BET) analysis. In addition, the electrode materials were electrochemically assessed through galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods in 6 M KOH electrolyte. Because of the synergistic impact of sulfur and metal, the prepared specimens showed excellent performance. Here, Zn-Co-S exhibited a high specific capacitance of 1646 F/g at 1 A/g current density. Furthermore, in our study, an asymmetric supercapacitor was developed successfully where active carbon and Zn-Co-S served as negative and positive electrodes, respectively. In the asymmetric device, a power density of 7080 W/kg and an energy density of 39.41 Wh/kg can be delivered with an 89 % capacitance retention followed by 2000 charge-discharge cycles. The results showed that the MOF-derived bimetal sulfide composite can be a promising candidate for the advanced electrode materials in supercapacitor applications.