3D layer shape electrode of NiS in-situ growth on shaddock peel derived carbon for high-performance supercapacitors

Abstract

Transition metal sulfide has excellent high electrical conductivity and excellent electrochemical activity. However, the use of transition metal sulfides as electrode materials still have two disadvantages. On one hand, their kinetic performance in redox reactions is poor. On the other hand, the Faraday redox reaction only occurs on the upper surface of the electrode material, and the short diffusion distance of the electrode into which the electrolyte enters makes it difficult to participate in the electrochemical charge storage inside the electrode, resulting in low energy density. Porous carbon has various pore structures and a large specific surface area. In addition, its surface possesses rich oxygen-containing active substances, which can enhance wettability. The addition of porous carbon to the sulfide can greatly improve its energy density. Hence, in this paper, a 5-SPC@NiS (NiS is grown in situ on grapefruit peel-derived carbon with a mass fraction of 5 %) with a layered sheet structure was synthesized by hydrothermal method, the specific capacitance of 5-SPC@NiS is as high as 1911 F g⁻¹ at 0.5 A g⁻¹. It also shows excellent electrochemical performance in practical applications, with an energy density of 14.6 Wh kg⁻¹ (supercapacitor) and 31.3 Wh kg⁻¹ (zinc ion battery). Overall, it provides a new solution to the energy challenges.