Structural, Morphological and Electrochemical Investigation of Cobalt Doped Strontium‐Nickel Ferrite for Energy Storage Supercapacitor

Abstract

Abstract In this study, Cobalt‐doped strontium‐nickel spinel ferrite samples, Co x Sr 0.5‐x Ni 0.5 Fe 2 O 4 , x = 0.0, 0.2, and 0.4, are successfully synthesized via the sol‐gel auto‐combustion method for supercapacitor applications. X‐ray diffraction (XRD) investigation verifies the generation of a highly crystalline, pure cubic spinel phase with face‐centered cubic structure (Fd‐3m space group). Fourier transform infrared spectroscopy (FTIR) validated the spinel structure through the observation of tetrahedral and octahedral metal–oxygen vibrations, with significant shifts in vibrational bands indicating successful Cobalt incorporation and cation redistribution. Field emission scanning electron microscopy (FESEM) images exposed the development of highly porous microstructures, with the x = 0.4 sample exhibiting the most uniform particle distribution and maximum porosity, beneficial for ion transport. Electrochemical analysis through cyclic voltammetry (CV) demonstrated that the x = 0.4 composition exhibited the largest enclosed area in the CV curves, indicating superior charge storage capability. Galvanostatic charge–discharge (GCD) measurements further confirmed that the x = 0.4 sample delivered the highest specific capacitance value of 12364.341 F g −1 at lower current densities, highlighting its excellent electrochemical performance. Overall, the Co x Sr 0.5‐x Ni 0.5 Fe 2 O 4 sample with x = 0.4 composition emerges as the most promising candidate for high‐performance supercapacitor electrodes, owing to its enhanced structural integrity, favorable porosity, and superior electrochemical behavior.