Design and fabrication of Bi₂S₃/Gr composite materials for investigating the performance of hybrid supercapacitors as advanced battery-type electrodes

In the present study, we report the growth of nanorod-shaped bismuth sulfide on the surface of layered graphene, forming a bismuth sulfide/graphene heterostructure. The distinctive architecture significantly amplifies its ion adsorption capacity, thereby endowing the material with outstanding electrochemical performance. The specific capacitance of the Bi₂S₃ electrode is determined to be 232.1 C g⁻¹ at a current density of 1 A g⁻¹. In contrast, the specific capacity could reach 528.9 C g⁻¹ when Bi₂S₃ is incorporated with graphene (Bi₂S₃/Gr-2). Furthermore, the Bi₂S₃/Gr-2 demonstrates an impressive cycling life retention rate of 85.5 % during a stability test of 10,000 cycles at a high current density (10 A g⁻¹). In contrast, the pure Bi₂S₃ only achieves a retention rate of 67.4 %. In a hybrid supercapacitor system, the positive electrode consists of Bi₂S₃/Gr, while activated carbon (AC) serves as the negative electrode. The optimal energy density values can reach up to 39.36 Wh kg⁻¹ at a power density of 800.09 W kg⁻¹, while maintaining excellent stability with a capacity retention rate of 97.5 % after undergoing 10,000 cycles at high current density. This study emphasizes the importance of advanced electrode materials for electrochemical energy storage and the conclusions，which offer crucial insights into the development of metal sulfides/graphene composite materials and their electrochemical performance.