Tailoring NiO nanostructures via solvent engineering: structural, optical and supercapacitor performance insights
摘要
We reported the electrochemical response of three solvent-derived NiO based electrode materials. Strategically, we used the solvents (2-methoxyethanol, 2-propanol and methanol) for synthesis process. The X-ray diffraction (XRD) analysis confirmed the crystalline structures of all samples. The sharp peaks affirmed the phase purity and exhibited a cubic phase structure of NiO for all three samples. However, the solvent based interatomic parameters including change in crystallite size, microstrain, and dislocation density are calculated. The interatomic changes observed in XRD analysis shown remarkable changes in electrochemical performance of the electrode material. The 2-methoxyethanol-driven NiO showed the excellent electrochemical performance. The sample displayed highest strain (4.11 × 10− 3), dislocation density (1.92 × 10− 3 nm− 2), and shortest crystallite size (22.83 nm). After examining the interatomic changes the Electrochemical Impedance Spectroscopy (EIS), Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet Visible Spectroscopy (UV-Vis spectroscopy) of all samples were analyzed. These evaluations tracked the outstanding performance of 2-methoxyethanol-based nickel oxide sample. Furthermore to observe the surface morphology we found a sponge-like, interconnected uniform nanostructure by using Scanning Electron Microscopy (SEM). The superior pseudocapacitive performance of the 2-methoxyethanol based NiO electrode material exhibited specific capacitance of 838.33 F g− 1 obtained at the scant rate of 1 A g− 1. After 5000 cycles, the electrode showed capacitive retention of 92% of its initial capacitance obtained at 3 A g− 1. The energy density of 10.5 Wh kg− 1 and a power density of 76 W kg− 1 at 1 A g− 1 were also obtained by using 2-electrode system. Redox-dominant behavior in alkaline media was corroborated by the significant capacitive contribution and b-value (0.6435) determined by Cyclic Voltammetry (CV) analysis, which verified improved charge storage kinetics. This work establishes 2-methoxyethanol as a feasible solvent for the production of high-performance supercapacitor electrodes, highlighting the crucial role of solvent engineering in obtaining the ionic-buffer-zone.