Tuning\nMOF-Derived Co₃O₄/NiCo₂O₄ Nanostructures for High-Performance Energy Storage

Abstract

Highly\nporous Co₃O₄/NiCo₂O₄ nanostructures\nwere synthesized using zeolitic imidazolate\nframework-67 (ZIF-67) nanocrystals. The oxide composite structure\nwas adjusted by modifying ZIF-67 crystallite size and the pore structure\nby the coordination modulation method. After forming the zeolite imidazolate\nframework-67 (ZIF-67)/Ni–Co layered double hydroxide intermediate\ncomposite through reaction with nickel nitrate, the intermediate composite\nwas heated in air to result in Co₃O₄/NiCo₂O₄. Nitrogen adsorption was used for pore structure\ncharacterization of the template and resultant oxide composite. The\nmaximum capacitance of nanostructured Co₃O₄/NiCo₂O₄ was 770 F g^–1 at a discharge\ncurrent density of 1 A g^–1 with acceptable cycle\nstability, maintaining 70% of the initial capacitance after 10,000\ncharge–discharge cycles.