Enhanced electrochemical performance of the MoS2/Bi2S3 nanocomposite-based electrode material prepared by a hydrothermal method for supercapacitor applications

Abstract

Supercapacitors are widely used energy storage systems in the modern world due to their excellent electrochemical performance, fast charging capability, easy handling, and high power density. In the present work, pure MoS₂ and MoS₂/Bi₂S₃ nanocomposites with different compositions of bismuth were synthesized by the hydrothermal method. The structural properties of the electrode materials were studied using the XRD technique, which confirmed the formation of MoS₂ and the secondary phase of Bi₂S₃ while increasing Bi substitution. The morphological studies of the synthesized electrode materials were performed using SEM, TEM, and HRTEM techniques, which indicated the 3D layered hierarchical structure of MoS₂ nanospheres and the nanosheet-like structure of Bi₂S₃. The electrochemical properties of pristine MoS₂ and MoS₂/Bi₂S₃ nanocomposites were analysed by CV, CP, and EIS techniques using a 2 M KOH electrolyte in a three-electrode system. The CV curves show evidence of significant improvement in the electrochemical performance of MoS₂/Bi₂S₃ composites compared to that of pure MoS₂. The calculated specific capacitances of MoS₂/Bi₂S₃ nanocomposites were relatively higher than those of pristine MoS_2. The 20 mol% Bi added sample showed a maximum specific capacitance of 371 F g⁻¹, compared to pristine MoS₂ and other samples at a current density of 1 A g⁻¹. The kinetics of the electrochemical process was studied. The Nyquist plots indicated that the Bi-added nanocomposites had lower R_esr and R_CT values, which resulted in high electrochemical performance. The experimental results revealed that Bi-substitution can further enhance the electrochemical energy storage performance of MoS₂ for supercapacitor applications.