Graphene and activated carbon-wrapped and Co3O4-intercalated 3D sandwich nanostructure hybrid for high-performance supercapacitance

• Published in: New journal of chemistry Vol. 42; no. 13; pp. 1733 - 174
• Main Authors: Li, Yue, Jia, Mengying, Xu, Lanshu, Gao, Jianmin, Zhang, Fan, Jin, Xiao-Juan
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2018
• Subjects: Activated carbon; Capacitance; Capacitors; Cobalt oxides; Electrochemical analysis; Flux density; Graphene; Transmission electron microscopy; X-ray diffraction
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c8nj01160e

A graphene/Co 3 O 4 /activated carbon (GCA) hybrid with excellent electrochemical properties for supercapacitance was successfully fabricated via a simple two-step hydrothermal method. The as-synthesized hybrid was examined by transmission electron microscopy (TEM), X-ray diffraction (XRD), and electrochemical characterization. The results confirmed that Co 3 O 4 particles were homogeneously distributed between the graphene and activated carbon layers. The GCA 1 : 9 capacitor (GC : AC = 9 : 1) showed the best electrochemical property compared with other hybrid capacitors. The specific capacitance of the GCA 1 : 9 hybrid capacitor is 564 F g −1 with activated carbon (AC) covering the outside of the graphene/Co 3 O 4 (GC) layers. The specific capacitance of the GCA 1 : 9 was improved by 53.26% compared with the GC composite capacitor (368 F g −1 ) at 50 mA g −1 in 7 M KOH. The GCA 1 : 9 also exhibits outstanding cycling property with 90.43% capacitance retention over 10 000 cycles at a current density of 20 A g −1 . Moreover, it also achieved a high energy density of 35.7 W h kg −1 at a power density of 235.5 W kg −1 , demonstrating that it is a promising candidate for supercapacitance. The graphene/Co 3 O 4 /activated carbon (GCA) 1 : 9 capacitor shows the best electrochemical properties with Co 3 O 4 particles that were homogeneously dispersed between the graphene/Co 3 O 4 (GC) layers.