Flexible N-doped heterostructure of cobalt sulfide and cobalt oxide composite electrodes derived from metal-organic frameworks and their electrochemical behaviors

Transition metal sulfides (TMSs) are considered as promising materials from the viewpoint of the higher capacitance, abundant redox sites and the higher electrical conductivity than transition metal oxides (TMOs). The heterostructure of the Co₃O₄ and CoS was synthesized, which derived from metal-organic frameworks, increased the electrochemical performances. Recently, in order to prevent the decrease of conductivity caused by the resistance of adhesive, there are some technologies growing directly on three-dimensional conductive substrates. In this study, by directly growing cobalt sulfide on carbon cloth (CC) which is a conductive material having excellent flexibility, can improve electrical conductivity and increase electrochemical activity efficiency. A hybrid supercapacitor device was manufactured and connected in series lighting four LEDs successfully. In addition, the cycling performance and mechanical properties of the device were tested, further demonstrating the excellent electrochemical performance of CoS/Co₃O₄/N-doped carbon nanosheets (NC)/CC electrode.