Optimizing Electrode Coating Techniques and Electrolyte Concentration for Enhanced Energy Storage in Spinel Cobaltite‐Based Supercapacitors

A series of experiments is conducted to evaluate the performance of newly developed spray‐coated electrodes in comparison with conventional slurry‐coated electrodes for supercapacitor applications. The assessment incorporates detailed morphological and electrochemical analyses to provide a comprehensive understanding of electrode behavior. At a current density of 1 A g −1 , the spray‐coated electrodes demonstrate specific capacitances of 550.67 F g −1 and 957.21 F g −1 in 1 m and 2 m KOH electrolytes, respectively. In contrast, slurry‐coated electrodes exhibit significantly higher capacitances, achieving 2023.0 F g −1 in 1 m KOH and 2578.0 F g −1 in 2 m KOH at the same current density. These findings highlight the superior electrochemical storage performance of slurry‐coated electrodes, which remain widely employed due to their ability to achieve high active material loading and excellent conductivity. However, the spray‐coating approach, though less commonly reported in the literature, presents a promising alternative fabrication method. Its capability to achieve uniform electrode surfaces, facilitate scalable production, and reduce processing complexity suggests considerable potential for further optimization. The values obtained in this study provide a strong basis for exploring spray‐coating as a viable, innovative technique for next‐generation energy storage devices, encouraging additional research to close the performance gap with slurry‐coated systems.