Tunable Electrochemical Properties of Cobalt-doped Praseodymium Oxide Perovskite via Sol-gel Synthesis for Supercapacitor Applications

Cobalt-doped praseodymium oxide (Pr1-xCoxO3) perovskite was successfully synthesized via the sol-gel method for enhanced electrochemical performance as supercapacitor electrodes. The doping strategy enabled precise control over the nanostructure, achieving an average particle size of approximately 20.65 nm with spherical, agglomerated morphology, as revealed by scanning electron microscopy. Energy-dispersive X-ray spectroscopy confirmed a uniform elemental distribution throughout the material. Brunauer–Emmett–Teller analysis showed a notable increase in surface area to 9.297 m2/g and a decreased pore volume of 0.062 cc/g compared to undoped Pr oxide, facilitating improved electrolyte diffusion and charge transport. Fourier-transform infrared spectrum exhibited characteristic metal–oxygen vibrational bands at 1554.82, 1410.10, and 657.96 cm-1, confirming the perovskite structure. X-ray photoelectron spectroscopy further validated the chemical states, identifying Pr3+ peaks at 933.84 and 944.04 eV, oxygen vacancies via O 1s peaks at 528.6 and 531.2 eV, and mixed Co2+ /Co3+ oxidation states through Co 2p peaks at ~780.1 and ~795.3 eV with satellite features. Electrochemical studies revealed a significant enhancement in specific capacitance, with the Co-doped material achieving 599 F/g at 3 A/g, substantially higher than the 270 F/g obtained for the undoped sample at 1 A/g. Furthermore, the electrode exhibited a high energy density of 27.5 Wh/kg and a power density of 4.9 kW/kg. These results demonstrate that cobalt incorporation effectively enhances charge storage capabilities, establishing Pr1-xCoxO3 perovskite as a highly promising candidate for next-generation supercapacitor applications.