MOF-assisted construction of Co9S8@Ni3S2/ZnS microplate array with ultrahigh areal specific capacity for advanced supercapattery

Transition metal sulfides are important candidates of battery-type electrode materials for advanced supercapatteries due to their high electric conductivity and electrochemical activity. Co9S8@Ni3S2/ZnS composite microplate array is prepared by a metal-organic framework assisted strategy since the electrochemical properties of composite arrays are governed by the synergistic effects of their diverse structures and compositions. As a battery-type material, Co9S8@Ni3S2/ZnS electrode expresses ultrahigh areal specific capacity of 8192 C cm-2 at the current density of 2 mA cm-2, and excellent cycling stability of 79.7% capacitance retention after 4000 cycles. An assembled supercapattery device using Co9S8@Ni3S2/ZnS microplate array as positive electrode and active carbon as negative electrode delivers a high energy density of 0.377 mWh cm-2 at a high power density of 1.517 mW cm-2, and outstanding retention of 95.2% after 5000 cycles. As a result, the obtained Co9S8@Ni3S2/ZnS has potential application in high-performance supercapatteries.