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 MoS2. 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 Resr and RCT 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.