Defect-Engineered Fe3C@NiCo2S4 Nanospike Derived from Metal-Organic Frameworks as an Advanced Electrode Material for Hybrid Supercapacitors

The rational synthesis and tailoring of metal-organicframeworks(MOFs) with multifunctional micro/nanoarchitectures have emerged asa subject of significant academic interest owing to their promisingpotential for utilization in advanced energy storage devices. Herein,we explored a category of three-dimensional (3D) NiCo2S4 nanospikes that have been integrated into a 1D Fe3C microarchitecture using a chemical surface transformation process.The resulting electrode materials, i.e., Fe3C@NiCo2S4 nanospikes, exhibit immense potentialfor utilization in high-performance hybrid supercapacitors. The nanospikesexhibit an elevated specific capacity (1894.2 F g(-1) at 1 A g(-1)), enhanced rate capability (59%), andexceptional cycling stability (92.5% with 98.7% Coulombic efficiency)via a charge storage mechanism reminiscent of a battery. The augmentedcharge storage characteristics are attributed to the collaborativefeatures of the active constituents, amplified availability of activesites inherent in the nanospikes, and the proficient redox chemicalreactions of multi-metallic guest species. When using nitrogen-dopedcarbon nanofibers as the anode to fabricate hybrid supercapacitors,the device exhibits high energy and power densities of 62.98 Wh kg(-1) and 6834 W kg(-1), respectively,and shows excellent long-term cycling stability (95.4% after 5000cycles), which affirms the significant potential of the proposed designfor applications in hybrid supercapacitors. The DFT study showed thestrong coupling of the oxygen from the electrolyte OH- with the metal atom of the nanostructures, resulting in high adsorptionproperties that facilitate the redox reaction kinetics.

Automated summary

This study explores the integration of 3D NiCo2S4 nanospikes into a 1D Fe3C microarchitecture, resulting in Fe3C@NiCo2S4 nanospikes electrode materials with great potential for high-performance hybrid supercapacitors.