A two-step approach to synthesis of Co(OH) 2/γ-NiOOH/reduced graphene oxide nanocomposite for high performance supercapacitors

• Published in: Frontiers of materials science Vol. 12; no. 3; pp. 273 - 282
• Main Authors: ZHAN, Ke, YIN, Tong, XUE, Yuan, TAN, Yinwen, ZHOU, Yihao, YAN, Ya, ZHAO, Bin
• Format: Journal Article
• Language: English
• Published: Beijing Higher Education Press 01.09.2018; Springer Nature B.V
• Subjects: Chemistry and Materials Science; Cobalt; cobaltous hydroxide; Electrochemical analysis; Electrode materials; Electrodes; Graphene; Materials Science; Metal foams; Nanocomposites; Nickel; reflux condensation; Research Article; supercapacitor; Supercapacitors; Synergistic effect; reflux condensation; graphene; cobaltous hydroxide; supercapacitor
• ISSN: 2095-025X; 2095-0268
• DOI: 10.1007/s11706-018-0432-1

A two-step approach was reported to fabricate cobaltous hydroxide/γ-nickel oxide hydroxide/reduced graphene oxide (Co(OH) 2/γ-NiOOH/RGO) nanocomposites on nickel foam by combining the reduction of graphene oxide with the help of reflux condensation and the subsequent hydrothermal of Co(OH) 2 on RGO. The microstructural, surface morphology and electrochemical properties of the Co(OH) 2/γ-NiOOH/RGO nanocomposite were investigated. The results showed that the surface of the first-step fabricated γ-NiOOH/RGO nanocomposites was uniformly coated by Co(OH) 2 nanoflakes with lateral size of tens of nm and thickness of several nm. Co(OH) 2/γ-NiOOH/RGO nanocomposite demonstrated a high specific capacitance (745 mF/cm 2 at 0.5 mA/cm 2) and a cycling stability of 69.8% after 1000 cycles at 30 mV/cm 2. γ-NiOOH/RGO//Co(OH) 2/γ-NiOOH/RGO asymmetric supercapacitor was assembled, and maximum gravimetric energy density of 57.3 W∙h/kg and power density of 66.1 kW/kg were achieved. The synergistic effect between the highly conductive graphene and the nanoflake Co(OH) 2 structure was responsible for the high electrochemical performance of the hybrid electrode. It is expected that this research could offer a simple method to prepare graphene-based electrode materials.