Development of three-dimensional MoSe2/graphene-flake composite toward high-performance symmetric supercapacitor: An experimental and theoretical study

Abstract

This work is an experimental and theoretical study in developing a symmetric supercapacitor composite of MoSe₂ and graphene flakes as electrodes. A theoretical analysis has been performed confirming the superior charge storage capability of the composite structure and its effectiveness as both active cathode and anode material in a symmetric supercapacitor. The three-dimensional MoSe₂-graphene flakes with different compositions are synthesized via the hydrothermal method. A notable electrochemical capacitance, specifically 748 F/g at 1 A/g demonstrates its potential as electrode material in supercapacitors. Additionally, the composite demonstrates a sufficiently high energy density of 48.7 Wh/kg at 1 A/g and a power density of 3 kW/kg at 5 A/g. Furthermore, the material has good stability, retaining 78 % capacity at 6 A/g with 94 % coulombic efficiencies even after 13,000 testing cycles. A pair of symmetric supercapacitors is used to illuminate sixteen red light-emitting diodes (LEDs) for up to 7.30 min. The device also exhibits satisfactory retention of electrochemical performance, when the bending test is carried out from 0^o to 165^o, showing good mechanical stability. The material thus shows significant promise in advanced energy storage applications, particularly within the high-performance flexible supercapacitor domain.