High-Energy-Density Quasi-Solid-State Supercapacitor with a MoS<sub>2</sub>@FeS<sub>2</sub> Core–Shell Heterostructure as an Advance Electrode Material
Abhijeet Singh, Muzahir Iqbal, Kiran Shankar Hazra, Santosh Kumar Mahapatra
Abstract
Metal chalcogenides with heterostructures exhibit fascinating structures and properties, enabling them to be used in various applications. In this work, we developed a core–shell heterostructure of MoS 2 @FeS 2 via a two-step hydrothermal and solvothermal method and explored its electrochemical performance in a quasi-solid-state symmetric and asymmetric supercapacitor. This unique heterostructure comprises MoS 2 nanoflakes decorated over octahedron-like FeS 2, which enhances the electron/ion mobility and provides more number redox sites to boost the electrochemical performance. The symmetric configuration exhibits a maximum specific capacitance of ∼386 F/g at a current density of 1 A/g, with an excellent capacitance retention of ∼90.3% over continuous 10 000 charge/discharge cycles at 10 A/g. Further, the heterostructure shows a high energy density of ∼53 Wh/kg at a power density of ∼699 W/kg. At the same time, the asymmetric configuration delivers a maximum capacitance of ∼186 F/g with energy and power density values of ∼29 Wh/kg and ∼900 W/kg, respectively. Two asymmetric cells connected in series can illuminate red and blue LEDs, conforming to their practical application. It is believed that the MoS 2 @FeS 2 core–shell heterostructure can be a promising electrode material for supercapacitor application.