Co3O4 nanocrystals derived from a zeolitic imidazolate framework on Ni foam as high-performance supercapacitor electrode material

A binder-free method was adopted to obtain a Ni foam/Co3O4 electrode. The Co3O4 nanocrystals with an average size of 15-25 nm deliver a high specific capacitance of 1680 F g(-1) at a current density of 0.5 A g(-1) in 1.0 M KOH electrolyte. Of particular note, the electrode exhibits a high capacitance retention rate of 58.3% at a current density of 15 A g(-1) with excellent electrochemical stability (15.9% specific capacitance loss after cycling 1000 times) even at high current density (5 A g(-1)), suggesting its promising application as a high-performance supercapacitor electrode material.