Enhanced electrochemical performance of the MoS 2 /Bi 2 S 3 nanocomposite-based electrode material prepared by a hydrothermal method for supercapacitor applications.

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 MoS 2 and MoS 2 /Bi 2 S 3 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 MoS 2 and the secondary phase of Bi 2 S 3 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 MoS 2 nanospheres and the nanosheet-like structure of Bi 2 S 3 . The electrochemical properties of pristine MoS 2 and MoS 2 /Bi 2 S 3 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 MoS 2 /Bi 2 S 3 composites compared to that of pure MoS 2 . The calculated specific capacitances of MoS 2 /Bi 2 S 3 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 MoS 2 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 MoS 2 for supercapacitor applications.