Novel 2D/2D NiCo2O4/ZnCo2O4@rGO/CNTs self-supporting composite electrode with high hydroxyl ion adsorption capacity for asymmetric supercapacitor. (10th November 2022)

• Record Type: Journal Article
• Authors: Chen, Xiumei; Xin, Na; Li, Yuxin; Sun, Cong; Li, Longhua; Ying, Yulong; Shi, Weidong; Liu, Yu
• Is Part Of: Journal of materials science & technology. Volume 127(2022)
• Page Start: 236
• Page End: 244
• Publication Date: 2022-11-10
• Subjects: Supercapacitor -- ZnCo2O4 -- NiCo2O4 -- Energy density -- Excellent conductivity -- High capacitance; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2022.04.009
• Languages: English
• ISSNs: 1005-0302

Abstract

Hightlights: NiCo2 O4 /ZnCo2 O4 hierarchical flakes vertically attached on graphene/carbon nanotube film are successfully prepared. The self-supporting film displays a high capacitance of 1128.6 F g −1 at 1 A g −1 . The electrode presents highly exposed active sites and optimal OH − adsorption. The supercapacitor delivers a high energy density of 50.8 W h kg −1 at 800 W kg −1 . Abstract: The energy storage device has been urgently studied and developed to meet the increasing demand for energy and sustainable development. Due to the excellent conductivity of graphene and high performance of ZnCo2 O4 and NiCo2 O4, we design a self-supporting electrode based on vertically grown two-dimensional/two-dimensional (2D/2D) NiCo2 O4 /ZnCo2 O4 hierarchical flakes on the carbon-based conductive substrate (NiCo2 O4 /ZnCo2 O4 @graphene/carbon nanotubes, NZ@GC). The density functional theory calculations indicate that the high OH − adsorption capacity of the NiCo2 O4 /ZnCo2 O4 nanosheets can significantly enhance the electrochemical reaction activity. NZ@GC shows a high capacitance of 1128.6 F g −1 at 1 A g −1 . The capacitance retains 84.0% after 6000 cycles even at 10 A g −1 . A hybrid supercapacitor is fabricated using NZ@GC and activated carbon, exhibiting a large energy density of 50.8 W h kg −1 at the power density of 800 W kg −1 . After 9000 charge/discharge cycles, the supercapacitor still has 86.1% capacitance retention. The NZ@GC film has showed the potential as promising electrodes in high efficiency electrochemical energy storage devices. Graphical abstract: Image, graphical abstract