Hierarchically Porous Biomass Carbon Derived from Natural Withered Rose Flowers as High-Performance Material for Advanced Supercapacitors

Herein, a hierarchically porous carbon was derived from the natural withered rose flower (denoted as RDPC) through a facile two-step method of carbonization and chemical activation with a mixture of KOH/KNO3. The as-derived RDPC contains an enlarged specific surface area of 1980 m(2) g(-1), better electrical conductivity and hierarchical porous architectures. Under three-electrode system with 6 M KOH electrolyte, the RDPC displays a wonderful electrochemical activity as supercapacitor electrode including of ultrahigh SC (350 F g(-1) at 1 A g(-1)), superb rate ability (165 F g(-1) even at 150 A g(-1)) and remarkable durability (only 4.4 % fading rate of capacitance after 140,000 cycles at 100 A g(-1)). The RDPC based symmetric supercapacitor with 6 M KOH electrolyte supplies the highest energy density of 15.6 Wh kg(-1) at 499 W kg(-1) with only 3.5 % decay rate of capacitance over 15,000 cycles at 20 A g(-1), which is revealing the excellent real application of RDPC in the supercapacitor. This extraordinary electrochemical performance of RDPC can be attributed to its uniform interconnected layered-like morphology, hierarchical porous networks, large specific surface area and fast electrochemical kinetics. Therefore, it is indicating that a facile and inexpensive designing of porous carbon from naturally available withered rose flowers and is a more sustainable electrode material for advanced energy storage related applications.