Bi-Fe chalcogenides anchored carbon matrix and structured core-shell Bi-Fe-P@Ni-P nanoarchitectures with appealing performances for supercapacitors

Pseudocapacitive materials based on multi-active components are attractive platforms for future portable energy devices due to their excellent redox processes and low cost. In this study, nanostructured bismuth-iron chalcogenide anchored on multiwalled carbon nanotube framework (Bi-Fe chalcogenide/C)-based electrode materials were fabricated via a simple solvothermal protocol with enhanced electrochemical performances. The obtained Bi-Fe chalcogenide/C nanocomposites combining the improved electroconductivity of carbonic frameworks and high pseudocapacitive properties of Bi/Fe reversible redox processes were employed as negative electrodes for asymmetric supercapacitor (ASC) devices. Systematic investigation of the synthesized materials and capacitive performance indicated that the Bi-Fe-P/C electrode simultaneously achieved an intrinsically appreciable specific capacitance of 532 F g^-1 at a current density of 1 A g^-1, high-rate capability, and cyclic stability, profiting from the structural and amorphous merits as well as the collaborative effect of multiple components. Besides, we employed an effective strategy to graft Bi-Fe-P film on a self-standing nickel phosphide (Ni-P) to manufacture a cathode with superior capacitive performances. The as-prepared core-shell Bi-Fe-P@Ni-P was used as a high-performance positive electrode and displayed a large specific capacitance of 230.6 mAh g^-1 at 1 A g^-1. Additionally, we also assembled an ASC system using the core-shell Bi-Fe-P@Ni-P as a positive electrode and amorphous Bi-Fe-P/C as a negative electrode with an expanded operational potential of 1.6 V. The hybrid device delivered a high specific energy density of 81.5 Wh kg^-1 at a power density of 890.2 W kg^-1 together with good cyclic characteristics (85.6% capacitance retention after 8000 consecutive cycles). The obtained findings offer new insights into the design of advanced energy storage materials at relatively low costs and underscore the proficiency of heterostructured multicomponent electrodes as a practical option for enhancing the electrochemical performance of ASC.