Synergistic effect of hydrothermal and physical activation approaches to fabricate activated carbon for energy storage applications

Carbon is the main constituent of all waste biomass. The extraction of activated carbonaceous materials from the waste biomass and their utilization in energy-storage applications is a green, cost-effective strategy. Herein, honeycomb-like activated carbon (AC) with a large surface area (2344 m2g-1) and improved conductivity was derived from palm seeds via hydrothermal followed by CO2 activation approaches. The AC sample was decorated over a carbon cloth (CC) current collector to form a flexible working electrode for next-generation electrochemical capacitors. As-prepared palm seed-derived activated carbon electrode delivered a good specific capacitance (Cs) of 294.9 Fg−1 @ 01 Ag−1, with exceptionally high cycling stability, showing 97.36% retention of its initial capacitance, even after 10,000 charge-discharge cycles in an alkaline electrolyte. The porous structure with microsized cavities enables the activated carbon-based electrode to show excellent rate capability (93.1% capacitance retention) even at nine-fold higher current density. As-prepared flexible electrode exhibits excellent electrochemical performance due to their unique three-dimensional network structure combined with porous architecture and good conductivity. This work provides a facile way to enhance activated carbon's capacitive performance and opens up new avenues for developing high-performance capacitive materials using waste biomass to reduce environmental concerns.