Ternary Co-Ni sulfides deposited on Co(OH)2 nanoflakes decorated carbon cloth as electrode for supercapacitor

Hierarchical Design of Co(OH)2/Ni3S2 Heterostructure on Nickel Foam for Energy Storage

In this study, we rationally designed a facile stepwise route and successfully synthesized a Co(OH)2/Ni3S2 heterostructure supported on nickel foam (NF) as a binder-free electrode for energy storage. Galvanostatic deposition was first applied to produce uniform Co(OH)2 nanoflakes on NF. Then, Ni3S2 was applied to its surface by potentiostatic deposition to form a Co(OH)2/Ni3S2 heterostructure at room temperature. The added Co(OH)2 not only functions as a practical electrochemically active component but also provides support for the growth of Ni3S2, and the deposition amount of Ni3S2 is controlled by adjusting the electrodeposition duration of Ni3S2. Then, the electrochemical behaviors of the Co(OH)2/Ni3S2 composite can be optimized. A maximum areal specific capacitance (Cs) of 5.73 F cm−2 at 2 mA cm−2 was achieved, and the coulombic efficiency was as high as 94.14%. A capacitance retention of 84.38% was measured after 5000 charge–discharge cycles.