Enhanced Electrochemical Performance of Eucalyptus Seed–Derived Activated Carbon for Supercapacitors
Anitha Nakka, Saraswathi Kailasa, Priyanka Jagnade, Prabhu Rajagiri, Akshay Kranth Allam, Venkatappa Rao TumuABSTRACT
Biomass‐derived porous carbon has emerged as a sustainable electrode material for supercapacitor applications. In this work, activated carbon (AC) was prepared from Eucalyptus seeds through a simple KOH activation process using an abundant and renewable biomass precursor. The synthesized carbon exhibited a hierarchical porous structure with a specific surface area of 610.248 m 2 g − 1 . Electrochemical measurements in 2 M KOH delivered specific capacitances of 266 F g − 1 in a three‐electrode configuration and 120 F g − 1 for the symmetric device in a two‐electrode configuration at 0.5 A g − 1 . Dunn's kinetic analysis revealed that charge storage was predominantly governed by surface‐controlled capacitive processes, while the porous architecture and oxygen‐containing surface functional groups promote efficient electrolyte transport and ion adsorption. The assembled symmetric supercapacitor delivered a maximum energy density of 11 Wh kg − 1 at a power density of approximately 200 W kg − 1 . It retained 6 Wh kg − 1 at approximately 1200 W kg − 1 , and maintained 76.5% capacitance retention after 10,000 charge–discharge cycles. The device also successfully powered five red LEDs for 13 s after a 10 s charging period, demonstrating its practical energy‐storage capability. These findings indicate that Eucalyptus seed‐derived AC is a sustainable and promising electrode material for supercapacitor applications.