Superior cyclic stability and electrochemical performance of La supported Bi2S3@g-C3N4//rGO heterostructure composite for asymmetric supercapacitor devices

Abstract

To improve the cyclic stability of Bi2S3 transition metal dichalcogenides (TMD), rare-earth lanthanum (La) supported Bi2S3@g-C3N4 was synthesized via a simple solvothermal method. The physicochemical properties of the electrode material were investigated by using various characterization techniques such as XRD, FTIR, FT Raman, HRSEM, XPS, BET, HRTEM and SAED. From HRTEM image that La doped Bi2S3@g-C3N4 heterostructure composite revealed in which the 2D layered g-C3N4 nanosheets decorated 1D nanorods of La doped Bi2S3. 10 mol% La doped Bi2S3@g-C3N4 heterostructure composite attained a higher specific capacity of 1880 C/g at 1 A/g by increasing active sites for diffusion ions due to enhanced surface area (131.4 m2/g). The aqueous asymmetric supercapacitor device was assembled using the La doped Bi2S3@g-C3N4 positive electrode and the rGO negative electrode with 1 M KOH electrolyte. This supercapacitor displayed a specific capacitance of 61 F/g at 2 mA/g, a maximum power density of 666 W/kg, an energy density of 1.7 W h/kg, and a capacitance preservation of 64% even after 10,000 cycles. 10 mol% La doped Bi2S3@g-C3N4 heterostructure composite persist excellent kinetic and electrochemical reversibility, intrinsic electrical conductivity, and remarkable cyclic stability.