The objective of this research is to modify an‎d optimize the structural an‎d morphological properties of nickel-cobalt hexacyanoferrate (Prussian blue) coatings on a graphite substrate to achieve maximum energy storage capacity. In this endeavor, the structure an‎d morphology of porous cobalt-nickel hexacyanoferrate (CoNiHCF) cubes were successfully modified by precisely adjusting the parameters of the synthesis bath using the co-precipitation method, including the molar ratio of the reactants, the reaction time an‎d temperature, an‎d the addition of ethanol to the synthesis bath. The CoNiHCF electrodes were characterized by X-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, an‎d the electrochemical tests of cyclic voltammetry an‎d electrochemical impedance spectroscopy. The results showed that the molar ratio of trisodium citrate an‎d the synthesis temperature have a significant impact on the structure, morphology, an‎d electrochemical performance of the electrodes. The CoNiHCF electrode synthesized at zero degrees Celsius, with a duration of 48 hours an‎d a trisodium citrate quantity of 387 mg, possessed the best energy storage properties. This electrode, with an average particle size of about 120 nanometers, demonstrated a specific gravimetric capacity of 1150 F/g in a 0.5 molar Na₂SO₄ electrolyte. Finally, the electrode synthesized under the optimal conditions was used to construct symmetric an‎d asymmetric supercapacitors. The symmetric supercapacitor, with an operating voltage range of 1.2 volts an‎d a Coulombic efficiency close to 100 percent at all current densities, along with a capacity retention of 91 percent over 3000 charge-discharge cycles, was able to illuminate blue, green, an‎d red LEDs for 3 minutes an‎d 10 seconds, 6 minutes an‎d 40 seconds, an‎d 8 minutes an‎d 11 seconds, respectively. Furthermore, the symmetric supercapacitor exhibited a power density of 2625 W·kg⁻¹ an‎d an energy density of 43.75 W·h·kg⁻¹, which indicates the superiority of the fabricated supercapacitor compared to many previous studies.

كيوان رئيسي

مريم كرباسي , مسعود عطاپور