Cattail fiber-derived hierarchical porous carbon materials for high-performance supercapacitors

Abstract Biomass-derived porous carbon materials are very promising in the fields of energy storage and conversion, owing to their fascinating features, such as superior renewability, low cost and environmental friendliness. Correspondingly, developing a safe and energy effective strategy for fabricating advanced carbon from biomass has drawn tremendous attention. In the present work, cattail fiber-derived porous carbon is prepared with an impregnation-single stage calcination method by using K2CO3 as the activating agent. The dosage of K2CO3 and calcination temperature are optimized according to the supercapacitive performance of the corresponding carbon materials. The optimal CPC-2-600, which is fabricated with a mass ratio of 2 : 1 for K2CO3 to cattail fibers and calcined at 600 °C, possesses much larger specific surface area and more abundant micropores and mesopores than the pristine carbon fabricated without using K2CO3 (denoted as CPC-0-600), leading to an improved supercapacitive behavior. As the electrode material for the three-electrode supercapacitors, CPC-2-600 displays a specific capacitance of 273.8 F g−1 at 1.0 A g−1 in 6.0 M KOH solution, as well superior rate capability. Moreover, the CPC-2-600-based symmetrical configuration delivers an energy density of 27.44 Wh kg−1 at 400 W kg−1. Even the power density is up to 8000 W kg−1, the energy density is still maintained as high as 16.67 Wh kg−1, which is much superior to CPC-0-600. Also, the symmetrical configuration exhibits good cycling stability. This work offers a hierarchical porous carbon from cattail fibers for high-performance supercapacitors. Moreover, the mild, effective and low-cost fabrication strategy is also suitable for preparing other biomass-based carbon, which is promising in heterogeneous catalysis, energy storage and conversion devices, and so on.