Nanoarchitectonics of Hierarchically Porous Carbon Materials from <i>Areca Catechu</i> Nut for Electrical Double-Layer Capacitor Applications

Abstract Precise tailoring of the surface texture and composition of porous carbon materials is crucial for enhancing the energy storage performance of the supercapacitors. Here, we report the fabrication of high-surface-area, self-nitrogen-oxygen-doped porous carbon materials from the sustainable carbon source, Areca catechu nut, by controlling the carbonization temperature (800-1000 °C) using alkali (KOH) as an activator in an inert nitrogen atmosphere. The material characterizations revealed ultra-high surface area of the carbon materials (2337 m2 g-1), with hierarchical micro- and mesoporosity and heteroatom retention (N, O) even at a high carbonization temperature of 900 °C. Activation significantly enhanced the surface textural properties, increasing the specific surface area and pore volumes from 57 to 2337 m2 g-1 and from 0.14 to 2.59 cm3 g-1, respectively. The electrochemical performance of the prepared carbon materials was then studied in a three-electrode cell configuration in an aqueous electrolyte (1 M H2SO4). The optimal sample, ANC_K1000, achieved a very high gravimetric capacitance of 410 F g-1 at a current density of 1 A g-1. The symmetric supercapacitor cell constructed with the optimal material delivered a decent energy density of 10.3 Wh kg-1 at the power density of 600 W kg-1, coupled with a capacity retention of 90.6% after 10,000 charge-discharge cycles. These results demonstrate a simple, facile, and sustainable method for fabricating biomass-derived porous carbon materials from Areca catechu nuts, which show immense potential as electrode materials for efficient energy storage in supercapacitors.