Ultrahigh capacitive performance of O and Mg self‐dual‐doped activated carbon from Ananas comosus leaf fiber using a redox additive‐based electrolyte

BACKGROUND The capacitive behavior of a supercapacitor (SC) based on activated carbon derived from biomass is enhanced when a halogenated iodide (in this case, iodide, Iˉ) is added to the acidic aqueous electrolyte. In this work, we prepared ultrahigh capacitive performance of O and Mg self‐dual‐doped activated carbon (AC) from Ananas comosus leaf fiber (ACLF) via chemical activation at high temperature, followed by activation under the protection of CO2 to produce commercially feasible electrodes for commercial‐scale SC devices. The prepared ACLFs were characterized through SEM–EDX, XRD, adsorption/desorption of N2. Moreover, in a 2‐electrode setup, the capacitive activity of the prepared ACLFs were evaluated using cyclic voltammetry and galvanostatic charge/discharge techniques in a redox additive electrolyte (1 M H2SO4 + 0.05 M KI). RESULT The pairs 3Iˉ/I3ˉ, 2Iˉ/I2, 2I3ˉ/3I2, and I2/IO3ˉ generate reduction–oxidation (redox) peaks in the CV curves and a significant Faradaic plateau in the GCD curves. The ACLF samples delivered an outstanding gravimetric capacitance and energy density as high as 581 F g−1 and 80.69 Wh kg−1 at a power density of 346.14 W kg−1, respectively. CONCLUSION The enhanced capacitive activity is a result of the Faradaic pseudocapacitance associated with the redox‐active ions present in the acidic electrolyte solution. This work describes a facile and economical approach to acquiring a potential candidate of electrode materials for SC devices with exceptional performance, achieved via a redox additive‐based electrolyte system. © 2023 Society of Chemical Industry (SCI).