Electrochemical studies on Cocos nucifera (coconut hair oil) derived carbon soot as an electrode material for EDLC application using non-aqueous NaPF6 electrolyte

Abstract

Abstract Cocos nucifera (Coconut hair oil) was burned using wick-and-oil technique (gas-phase combustion) known as flame synthesis method to obtain carbon soot for electrode material. Synthesized carbon soot was chemically activated using optimized ratio of activating agents ZnCl 2 (1:1, wt. /wt.) and KOH (1:2, wt./wt.), followed by thermal treatment at 900 °C. XRD analysis showed that the coconut oil-derived carbon soot (CoCS) has a crystallite size of ~ 1.92 nm with an interlayer spacing of 3.62 Å. After chemical activation, the crystallite size slightly altered only, while a small increase in interlayer spacing was observed (3.65 Å for ZnCl₂ activation and 3.71 Å for KOH activation), revealing subtle structural modification of the carbon framework. SEM analysis revealed a well-connected microporous network with reduced agglomerate size after activation, while EDAX confirmed increased carbon content following chemical treatment. BET results showed a substantially enhanced surface area and mesoporous structure of the KOH-activated CoCS, leading to favorable pathways for electrolyte ion transport. Among the studied samples, KOH-activated CoCS demonstrated the best electrochemical performance, delivering a specific capacitance of ~ 176 F g⁻¹, with an energy density of ~ 6.11 Wh kg⁻¹ and a maximum power density of ~ 395 W kg⁻¹. The simple synthesis route, favorable structural characteristics, and competitive electrochemical performance highlight the potential of coconut oil-derived carbon soot as a scalable and sustainable electrode material for EDLC and other energy storage applications.