Surface engineering of MOFs-derived Co₃O₄ nanosheets for high-performance supercapacitor

In this work, hierarchical edge-rich Co₃O₄ nanosheets (e-Co₃O_4NSs) arrays were synthesised on the surface of Ni foam via a self-templating technique using metal-organic frameworks (MOFs) as precursors. The morphology and surface of Co₃O_4NSs could be tailed using the potassium hexacyanocobaltate solution. The synthesised e-Co₃O_4NSs shows that numerous small nanosheets were in-situ grown on the large nanosheet substrates, forming a core-shell structure, which could provide more active sites for electrochemical reactions. Benefiting from the structural superiorities, the e-Co₃O_4NSs/Ni foam as supercapacitor electrode exhibits a high specific capacitance of 523 F g⁻¹, good rate capability (67.1% of capacitance retention at 10 A g⁻¹), as well as excellent cycling stability (89.6% of capacitance retention after 3000 cycles).