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Coconut coir dust (CCD) is a byproduct generated during the separation process of coconut coir fiber from coconut husk. Due to its high carbon content and relatively low ash content, utilizing CCD as a precursor for carbon production is an attractive option. In this work, activated carbons (ACs) were synthesized from CCD through carbonization at 500, 600, and 700 ºC, followed by steam activation at 900 ºC. The morphology of ACs exhibited a rougher and more ruptured surface after steam activation. All ACs displayed an amorphous carbon phase with a small presence of impurities. Upon activation, the chemical functional groups disappeared, confirming the conversion of the lignocellulosic structure into a carbon material. The specific surface area of ACs derived from carbonized samples at 500, 600, and 700 ºC was 802, 779, and 889 m2/g, respectively. This surface area was contributed by micropores (57–67%) and meso-macropores (33–43%), indicating that the pre-carbonization temperature influenced the development of porosity and surface area of the ACs. The potential application of CCD-derived ACs as supercapacitor electrodes was evaluated using a three-electrode system by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) in a 6 M KOH electrolyte. All ACs exhibited a quasi-rectangular CV curve with no re-dox peaks and nearly linear triangular GCD curves, indicating the electrical-double layer capacitor (EDLC) behavior. The AC (carbonized at 700 ºC) had the highest specific capacitance (~90 F/g at 1 A/g), attributed to its highest surface area. Furthermore, it was chosen for fabricating a coin-cell supercapacitor (two-electrode system) for practical applications. The coin cell was tested through 1,000 charge-discharge cycles to confirm its potential for long term use. The results of this study highlight the potential of CCD-derived ACs as electrode materials for supercapacitor applications.
