Preparation of porous layered cobalt-zinc sulfide nanostructures based on graphene oxide supported ZIF-8 template for high-performance supercapacitors

As a new environment-friendly energy storage system between traditional capacitors and lithium-ion batteries, supercapacitors have many excellent characteristics compared with other energy storage devices. The new electrode material is the key component to determine the performance of the supercapacitor. Combined with the relevant literature reports of researchers in recent years, the structure and properties of Co, Zn, Ni and other materials were introduced, and the preparation method of Co–Zn as electrode material was sorted out. The rGO/Zn0.773Co0.227S composites were prepared by a simple template method to analyze the structure and morphology, and rGO/Zn0.773Co0.227S was treated to make it a paste adhering to nickel foam. Benefiting from the synergistic effect between Zn0.773Co0.227S and rGO, the composite provides significantly improved energy storage capability in a three-electrode system. The specific capacitance can reach 1680 ​F ​g−1 at the current density of 1 ​A ​g−1. When the current density is increased to 10A g−1, the specific capacitance still reaches 895.4 ​F ​g−1, and the loss of the specific capacitance is only 22.2% after 5000 cycles at 10 ​A ​g−1. When rGO/Zn0.773Co0.227S is used as cathode material and AC as negative material, asymmetric supercapacitor also has good cycle stability and high energy density.