Augmenting the performance of thermally deoxygenated graphite oxide supercapacitor electrodes using 6 M KOH electrolyte with K3Fe(CN)6 redox additive

This study focuses on enhancing the performance of thermally deoxygenated graphite oxide (TDGO) supercapacitor electrodes by incorporating a redox additive viz., 0.03 M K3Fe(CN)(6) in 6 M KOH. Characterization of the prepared TDGO was conducted through XRD, Raman, XPS, FESEM and BET surface area analysis, revealing incomplete deoxygenation and the presence of oxygen functional groups. TDGO exhibits a maximum significant surface area of 288.3 m(2) g(-1) with an average pore diameter of 2.4 nm. The I-D/I-G ratio of 0.98 suggests the prevalence of structural defects dominating the sp(2) graphitic structure. FESEM images reveal exfoliated irregular layers in TDGO. In a three-electrode configuration, the optimized system achieves an areal specific capacitance (C-sp) of 817 F cm(-2) at 1 A g(-1), a 2.5-fold increase compared to 6 M KOH alone. The [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) redox couple in the electrolyte alters the charge storage mechanism from surface-controlled to diffusion-controlled pseudocapacitance. A symmetric TDGO300 supercapacitor in the KOH/K3Fe(CN)(6) redox electrolyte system exhibits a C-sp of 414.6 F cm(-2), delivering an energy density of 17.4 W h kg(-1) at a power density of 235 W kg(-1). Notably, the TDGO300 supercapacitor retains 97.4% of its initial capacitance after 2000 continuous charge-discharge cycles. This work establishes a straightforward strategy to significantly improve the capacitive performance of TDGO supercapacitors by leveraging redox additives, showcasing their potential for advanced energy storage applications.