Anchoring ternary NiCoMn-S ultrathin nanosheets on porous ZnCo2O4 nanowires to form core-shell composites for high-performance asymmetric supercapacitor

Abstract Successful synthesis of novel multi-component metal composites with a unique structure can effectively promote the electrochemical performance improvement of supercapacitors. Herein, three-dimensional (3D) ZnCo2O4@NiCoMn-S(denoted as ZnCo2O4@NxCyMzS-X, x, y and z refer to the element content ratio, X refers to the number of cycles) arrays growing on nickel foam (NF) were synthesized with facile hydrothermal and electrodeposition processes. The structure of samples is regulated with the molar content of Ni/Mn ions and deposition time in electrodeposition. ZnCo2O4@N1C2M1S-4 with optimal hierarchical structure shows a high area capacity of 7.04 C·cm-2 under 2 mA·cm-2 (1671 C·g-1 at 1.1 A·g-1) and cycle retention rate of 76.48% after 3000 cycles under 50 mA·cm-2. Furthermore, a ZnCo2O4@N1C2M1S-4//Active Carbon (AC) hybrid supercapacitor (HSC) was assembled to test the practical application of ZnCo2O4@N1C2M1S. It is shown the voltage window of HSC achieves as high as 1.9 V, and it reveals a high energy density of 64.36 Wh·kg-1 under a power density of 0.95 kW·kg-1 along with great stability with 75% retention at 5 A·g-1 after 5000 cycles, showing a broad prospect in the field of energy storage. At the time, this study provides a reference for material structure design.