MnO2/ZnCo2O4 with binder-free arrays on nickel foam loaded with graphene as a high performance electrode for advanced asymmetric supercapacitors. Issue 56 (15th October 2019)

• Record Type: Journal Article
• Authors: Cong, Wanjuan; Miao, Rui; Tao, Bairui; Miao, Fengjuan
• Is Part Of: RSC advances. Volume 9:Issue 56(2019)
• Page Start: 32889
• Page End: 32897
• Publication Date: 2019-10-15
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9ra04598h
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Schematic illustration of formation process of MnO2 /ZnCo2 O4 /G/NF composite electrode. Abstract : ZnCo2 O4 nanosheets were successfully arrayed on a Ni foam surface with graphene using a hydrothermal method followed by annealing treatment; then MnO2 nanoparticles were electrodeposited on the ZnCo2 O4 nanosheets to obtain a synthesized composite binder-free electrode named MnO2 /ZnCo2 O4 /graphene/Ni foam (denoted as MnO2 /ZnCo2 O4 /G/NF). After testing the binder-free composite electrode of MnO2 /ZnCo2 O4 /G/NF via cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy testing, we found that it exhibited ultrahigh electrochemical properties, with a high specific areal capacitance of 3405.21 F g −1 under a current density of 2 A g −1, and wonderful cycling stability, with 91.2% retention after 5000 cycles. Moreover, an asymmetric supercapacitor (ASC) based on MnO2 /ZnCo2 O4 /G/NF//G/NF was successfully designed. When tested, the as-designed ASC can achieve a maximum energy density of 46.85 W h kg −1 at a power density of 166.67 W kg −1 . Finally, the ASC we assembled can power a commercial red LED lamp successfully for more than 5 min, which proves its practicability. All these impressive performances indicate that the MnO2 /ZnCo2 O4 /graphene composite material is an outstanding electrode material for electrochemical capacitors.