Co3O4 and Co(OH)2 loaded graphene on Ni foam for high-performance supercapacitor electrode

Electrode materials with high conductivity and excellent redox characteristics are vital to supercapacitors in electrochemical energy storage. Herein, a graphene/Co3O4/Co(OH)2/Ni electrode synthesized hydrothermally has high specific capacitance and the morphology and structure of the graphene/Co3O4/Co(OH)2/Ni electrodes are characterized systematically. The three electrode charge–discharge test exhibits an excellent specific capacitance of 3216 F g−1 at 5 A g−1. The two electrode charge–discharge capacitance decreases from an initial value of 195 to 140 F g−1 after 5000 cycles showing capacitance retention of 71.1%. A test device is fabricated with (OH)2/Co3O4/graphene/Ni as the positive electrode and carbon/nickel foam as the negative electrode. After charging for 15 s, two such devices in series can efficiently power five 5-mm-diameter light-emitting diodes (LEDs) and the excellent electrochemical performance reveals large potential in next-generation high-performance supercapacitors.