Hierarchical Activated Green Carbons from Abundant Biomass Waste for Symmetric Supercapacitors

Hierarchically porous activated carbons (ACs) derived from apricot shell (AS), which is a low-cost and abundant carbon source from a renewable and sustainable biomass waste, were prepared by a green and facile approach via carbonization followed by steam activation and applied to electrodes for symmetric supercapacitors (SCs). The as-obtained AC possessed large surface area and developed porosity with hierarchical pore texture, leading to the specific capacitance of 38.3 F g−1 for an AC//AC symmetrical SC in 20 wt% H2SO4 aqueous electrolyte. Moreover, the assembled AC//AC SC exhibited superior cycling life stability with 99% retention after 6000 cycles at 5 A g−1. These results demonstrate that the present facile, low-cost, and environmentally friendly synthetic strategy for hierarchical ACs from AS can promote the utilization and conversion of AS to high value-added industrial products as well as commercial applications in energy storage devices.