Boosting the pseudocapacitive response of spinel CoFe₂O₄ nanoparticles obtained by chemical hydrolysis via fine tuning their thermal-microstructural properties

Nanocrystalline spinel CoFe₂O₄ materials have been successfully synthesized by a facile force-driven chemical hydrolysis technique, and the impacts of varying post-synthesis annealing temperature on their morphological, structural, and electrochemical properties have been investigated. Microstructural investigation revealed the formation of a spinel cubic structure of a typical CoFe₂O₄ nanoparticle, which showed enhanced microstructural properties upon increasing annealing temperature. The optimally improved microstructure, coupled with the exhibition of favorable electrochemical and electrical properties of the CoFe₂O₄ sample annealed at 800 °C, resulted in an enhanced pseudocapacitive charge storage performance with maximum specific capacitance and capacity values of 756.5 Fg⁻¹ and 57.16 mAhg⁻¹. The presence of interstitial sites enabled fast and efficient ion transport and diffusion attributes for the high electrochemical charge storage outputs. The obtained results suggest that the effectiveness of CoFe₂O₄ as electrode materials for electrochemical energy storage depends on its microstructural build-up via thermal treatment variations.