Island-like Ni–V–Fe Phosphide Heterostructures on Fe-Doped NiV-MOF Nanoflowers for Enhanced Supercapacitors

Metal-organic frameworks (MOFs) and their derived heterostructures show significant potential in supercapacitors due to their unique electronic properties and interfacial effects. Here, Fe-doped NiV-MOF nanoflowers are synthesized on nickel foam (NF) via a solvothermal method, followed by in situ decoration of Ni-V-Fe phosphides (NiVFe-P) on the nanosheets to construct the island-like heterostructure (NiVFe-P@NiVFe-MOF/NF) through partial phosphorization. This island-like heterostructure possesses excellent electrical conductivity and adsorption performance, which are beneficial to enhance the rapid transfer efficiency of electrons/ions and the capability of charge storage. Therefore, NiVFe-P@NiVFe-MOF/NF delivers a high specific capacity (2319.3 C g^-1 at 1 A g^-1) and a remarkable stability (87.2% retention after 10,000 cycles). The assembled hybrid supercapacitor (NiVFe-P@NiVFe-MOF/NF//AC/NF) achieves an energy density of 109.4 Wh kg^-1 at 1.16 kW kg^-1 with an outstanding cycle life (93.4% retention after 10,000 cycles). This work highlights the potential of island-like heterostructures as a promising strategy for developing advanced supercapacitor electrodes.