Significant Potential of Cocos nucifera L. Bunches Waste as Carbon Source for Sustainable Electrode Material Supercapacitors

Abstract

The interest in utilizing biowaste materials to produce carbon source, especially for electrode materials in physicochemical energy storage devices like Li-ion batteries and supercapacitors, is driven by concerns regarding energy cost-effectiveness and environmental pollution. This study specifically concentrates on the utilization of waste from Cocos nucifera L. bunches as an eco-friendly source of carbon source designed for supercapacitor electrodes. The precursors chosen in this study were old Cocos nucifera L. bunches and young Cocos nucifera L. bunches. The preparation involves chemical activation of the waste using a 0.5 M potassium hydroxide solution at 900°C, with pyrolysis occurring in an nitrogen and carbon dioxide gas environment. The resultant activated carbon, configured as monolithic coins, retains its structure by optimizing the bonding characteristics of the precursor, eliminating the necessity for supplementary adhesives. Every coin-shaped monolith displays carbon structures ranging from turbostratic to highly amorphous. Electrochemical testing in a symmetric supercapacitor showed old Cocos nucifera L. bunches a high specific capacitance of 262 F g−1 at a constant density of 1.0 A g−1. Furthermore, the maximum energy density was determined to be 3.54 Wh kg−1 at an optimal power density of 85 W kg−1 in 1 M H2SO4 aqueous electrolyte. Utilizing waste, combined with a straightforward preparation process and remarkable electrochemical properties, positions carbon source derived from aged Cocos nucifera L. bunches as a prospective and sustainable electrode material for energy storage applications in supercapacitors.