Sulphur/mechanochemical graphene/Bi2S3 as a 3D-nanoflowers composite cathode for high-performance lithium-sulfur coin-cell

This study employs a hydrothermal approach to synthesize bismuth sulfide (Bi₂S₃) 3D nanoflowers, which consists of primary nanorods. A composite material comprising sulfur, mechanochemically processed graphene (MCG), and Bi₂S₃ (3D) nanoflowers (S/MCG/Bi₂S₃ (3D)) is investigated as a cathode for lithium-sulfur (Li-S) batteries. The composite and its constituents are characterized using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-rays spectroscopy (EDAX). The electrochemical properties of Bi₂S₃ (3D) nanoflowers, MCG, and the S/MCG/Bi₂S₃ (3D) composite are assessed through cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). The S/MCG/Bi₂S₃ (3D) composite demonstrated an outstanding specific capacitance of 646.41 F/g, retaining 99.61% of its capacity even after 1000 cycles. When used as a cathode in a coin cell, it delivered an approximate voltage of 3.44 V. Additionally, the coin cell maintained a stable potential of 3.02 V while continuously powering a yellow-emitting LED for 2 h.