Electrochemical Iodination of Graphene Oxide via Redox Additive Electrolyte: A New Approach for High‐Capacitance Supercapacitors

Halogenated graphene oxide (GO), offers a powerful strategy to tailor its structure and enhance electrochemical performance. Incorporating halogen atoms or ions induces a hybridization shift from sp 2 to sp 3 in graphene, significantly altering its local structure and electronic properties. In this study, an eco‐friendly and rapid electrochemical method is presented using an optimized redox additive concentration of 0.6 M KI in a 3 M KOH electrolyte to introduce iodine species into the GO matrix, resulting in the formation of iodinated graphene oxide (I‐GO). The formation of I‐GO is systematically studied via Raman spectroscopy, x‐ray photoelectron spectroscopy, scanning electron microscopy and energy‐dispersive x‐ray spectroscopy analyses. Structural and morphological characterizations confirm the successful integration of iodine and partial reduction of GO. The I‐GO electrode demonstrated a maximum specific capacitance of 379.2 F g −1 at a current density of 3 A g −1 endorsing its excellent energy storage capacity. The fabricated I‐GO symmetric supercapacitor coin cell device shows energy density of 24.9 Wh kg −1 and power density of 11.2 kW kg −1 while maintaining 82% capacitance retention after 5000 cycles at 10 A g −1 . These findings highlight the potential of I‐GO as a promising candidate for next‐generation energy storage systems.