| Autor: |
Bandas C; Condensed Matter Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, 1 Plautius Andronescu Street, 300254 Timisoara, Romania., Nicolaescu M; Condensed Matter Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, 1 Plautius Andronescu Street, 300254 Timisoara, Romania.; Department of Materials and Manufacturing Engineering, Faculty of Mechanical Engineering, Politehnica University of Timisoara Mihai Viteazu 1, 300222 Timisoara, Romania., Popescu MI; Condensed Matter Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, 1 Plautius Andronescu Street, 300254 Timisoara, Romania.; Department of Applied Chemistry and Engineering of Inorganic Compounds and Environment, Politehnica University of Timisoara, Blv. Vasile Parvan 6, 300223 Timisoara, Romania., Orha C; Condensed Matter Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, 1 Plautius Andronescu Street, 300254 Timisoara, Romania., Căprărescu S; Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Chemical Engineering and Biotechnologies, University 'Politehnica' of Bucharest, Polizu Street No. 1-7, 011061 Bucharest, Romania., Lazau C; Condensed Matter Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, 1 Plautius Andronescu Street, 300254 Timisoara, Romania. |
| Abstrakt: |
Zn-ZnO(Nw)-rGO hybrid electrodes for supercapacitor applications were successfully prepared in situ by a one-step microwave-assisted hydrothermal method by deposition of reduced graphene oxide (rGO) on the structure of ZnO nanowires grown on the Zn foil. During the hydrothermal treatment, two processes occur the reduction of graphene oxide (GO) and the deposition of rGO on the Zn-ZnO(Nw) support. The growth of ZnO nanowires was achieved by thermal oxidation below the melting point of the Zn foil in a controlled atmosphere. The as-obtained electrodes were assessed for structural, optical, and morphological properties by X-ray diffraction, Raman spectroscopy, ultraviolet-visible spectroscopy, SEM microscopy, and EDX analysis. The supercapacitor properties of the Zn-ZnO(Nw)-rGO hybrid electrodes were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge analysis. The CV curve reveals that the Zn-ZnO(Nw)-rGO hybrid structures work as negative electrodes and exhibit a non-ideal rectangle-like shape, suggesting that the as-synthesized structure behaves as a pseudo-capacitor. A maximum capacitance was determined to be 395.79 mF cm -2 at a scan rate of 5 mV s -1 . Based on GCD analysis, the maximum specific capacitance of 145.59 mF cm -2 was achieved at a low power density of 2 mA cm -2 . The cycle life assessment of the Zn-ZnO(Nw)-rGO hybrid electrode over a 250-cycle number was performed by CV and GCD analysis. The maximum retention rate of 120.86% was achieved from GCD analysis over 250 cycles for the Zn-ZnO(Nw)-rGO hybrid electrode. |
