3D Hierarchical structure Electrodes of MnO2 Nanosheets Decorated on Needle‐like NiCo2O4 Nanocones on Ni Foam as a cathode material for Asymmetric Supercapacitors. Issue 19 (21st May 2019)

• Record Type: Journal Article
• Authors: Ren, Bo; Fan, Meiqing; Yang, Xiaodong; Wang, Lei; Yu, Haixia
• Is Part Of: ChemistrySelect. Volume 4:Issue 19(2019)
• Page Start: 5641
• Page End: 5650
• Publication Date: 2019-05-21
• Subjects: Hierarchical -- MnO2 nanosheets/needle-like NiCo2O4 nanocones -- hybrid arrays -- biochar -- asymmetric supercapacitor; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201901018
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: In this work, three dimensional (3D) hierarchical structure electrode of MnO2 nanosheets decorated on needle‐like NiCo2 O4 nanocones hybrid arrays on Ni foam is designed by a two‐step hydrothermal process. In this special structure, 3D hierarchical NiCo2 O4 /MnO2 core/shell composites have high specific surface area and large pore structure, which makes it easier to reach the active site, and shorten the ion transport path. Used as electrode for supercapacitors, the composites can develop their respective strengths, and the synergies between different components can also improve capacitance and speed capacity. The electrochemical results exhibit that the NiCo2 O4 /MnO2 core/shell electrodes display a large capacitance of 816 F⋅g −1 at the current density of 5 mA⋅cm −2, and show an excellent cycling stability (81% retention after 5000 cycles). Four Asymmetric supercapacitors (NiCo2 O4 /MnO2 //BPC (banana peel), NiCo2 O4 /MnO2 //BHC (buckwheat husk), NiCo2 O4 /MnO2 //PPC (pomelo peel), and NiCo2 O4 /MnO2 //AC (activated carbon)) using the NiCo2 O4 /MnO2 core/shell as a positive electrode and biochar as a negative electrode are assembled. The results indicate that all the asymmetric supercapacitors deliver a high operation voltage of 1.6 V, and NiCo2 O4 /MnO2 //BPC exhibits excellent specific capacitance (85.4 F⋅g −1 at the current density of 5 mA⋅cm −2 ), high energy density (30.4 Wh⋅kg −1 at the power density of 133.5 W⋅kg −1 ) and remarkable cycling stability (only decrease by 12% after 5000 cycles). Abstract : Three dimensional (3D) hierarchical structure electrodes of MnO2 nanosheets decorated on needle‐like NiCo2 O4 nanocones hybrid arrays on Ni foam is designed by a two‐step hydrothermal process. To further evaluate the NiCo2 O4 /MnO2 core/shell composite electrode for real application, a series of asymmetric supercapacitor devices are assembled by using the NiCo2 O4 /MnO2 core/shell composite as a positive electrode and three types of biochar (pomelo peel (PPC), banana peel (BPC) and buckwheat hull (BHC)) are used as negative electrodes. The results indicate that all the asymmetric supercapacitors deliver a high operation voltage of 1.6 V, and NiCo2 O4 /MnO2 //BPC exhibits outstanding capacitive behaviors.