Porous NiCo2O4 electrodes for high-energy asymmetric supercapacitor: effect of annealing

• Published in: Journal of materials science 2023-06, Vol.58 (23), p.9586-9604
• Main Authors: Thorat, J. P., Nikam, R. P., Lokhande, V. C., Lokhande, C. D.
• Format: Article
• Language: English
• Subjects: Adsorption; Annealing; Asymmetry; Characterization and Evaluation of Materials; Chemical synthesis; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Electrochemical analysis; Electrodes; Electrolytes; Emission analysis; Energy Materials; Energy storage; Field emission spectroscopy; Materials Science; Microspheres; Morphology; Nickel compounds; Polymer Sciences; Solid Mechanics; Supercapacitors; Temperature effects; Thin films
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-023-08602-4

Nickel–cobalt hydroxide thin films were synthesized using the chemical bath deposition method, and the effect of thermal annealing (373–673 K) on their physicochemical and electrochemical characteristics was explored. The X-ray diffraction study showed a cubic crystalline structure of NiCo 2 O 4 electrode formed above annealing temperature of 573 K. Field emission scanning electron spectroscopy (FE-SEM) study revealed that after annealing, NiCo 2 O 4 electrode showed urchin-like microspheres morphology with superhydrophilic nature. The electrode annealed at 573 K exhibited outstanding electrochemical performance with a specific capacitance of 470 F g −1 at 0.4 A g −1 current density. Over 2000 cycles, electrode demonstrated capacitive retention of 75.55%. Finally, NiCo 2 O 4 and Fe 2 O 3 thin films were used to construct the asymmetric supercapacitor (ASC) device. The ASC device manifested energy density of 40 Wh kg −1 at power density of 1.66 kW kg −1 and 82% retention after 2000 CV cycles. Graphical Abstract