(Fe,Ni,Co)Se/MoSe2 Polymetallic Nanohybrids: Synergistic Dual Regulation for Enhanced Hybrid Supercapacitor Performance

Abstract Metal–organic framework (MOF) derivatives used as supercapacitor electrode materials generally suffer from poor intrinsic conductivity and inadequate capacitive performance, so, it is crucial to enhance their electrochemical performance through rational nanoscale design. In this study, nanoscale structure engineering is exploited to construct a hollow nanostructure with tailored morphology and optimized electronic properties. A hollow structure was first constructed via Ni(NO3)2 and Co(NO3)2 etching MIL101(Fe) as a template. Finally, combining molybdate ion intercalation and selenization treatment, the multimetal selenide materials (hereinafter referred to FNCLM/S) were successfully synthesized. The synergy between the intercalation and selenization is systematically optimized to simultaneously modulate the electronic structure, interlayer environment, and morphology of the resulting material, thereby significantly enhancing the electrochemical kinetics. Owing to the short ion transport paths provided by the hollow structure, the electrolyte penetration facilitated by the loose particle packing structure, and synergistic effects among the multimetal components, the prepared FNCLM-0.5/S-500 ((Fe, Ni, Co)Se/MoSe2) electrode exhibited an excellent specific capacitance of 2368.99 F·g–1 at a current density of 1 A·g–1 in a three-electrode system. A hybrid supercapacitor assembled with this material as the cathode and activated carbon as the anode can operate stably over a wide voltage window of 1.53 V. It achieved an energy density of up to 100.34 Wh·kg–1 at a power density of 764.98 W·kg–1, with a capacity retention rate of 75% and a Coulombic efficiency approaching 100% after 6,000 charge–discharge cycles. Furthermore, the device successfully powered a commercial timer for nearly 20 min, demonstrating excellent potential for practical applications. This work offers a feasible intercalation–selenization combined strategy for MOF-derived multimetal material preparation toward high-performance hybrid supercapacitors.