Donut-shaped Co3O4 nanoflakes grown on nickel foam with enhanced supercapacitive performances

The as-synthesized product exhibits a high initial discharge capacitance of 518 mF/cm2 at a current density of 1 mA cm−2 and can maintain 75% capacitance retention even after 6000 charge-discharge cycles. Electrochemical results revealed that the prepared Co3O4 nanoflakes possess a remarkable performance in supercapacitor applications.