Construction of hierarchically porous biomass carbon using iodine as pore-making agent for energy storage

High specific surface area, hierarchical porosity, high conductivity and heteroatoms doping have been considered as the dominating factors of high-performance carbon-based supercapacitors. Inspired by the blue phenomenon of combination of starch and iodine, iodine is employed firstly as pore-making agent to create micropores for the starch-derived carbon in this study. Based on this mechanism, the hierarchically porous carbon is synthesized through simple solvent heating and high-temperature (1000 degrees C) carbonization, which achieves high specific surface area of 2989 m(2) g(-1) (an increase of 39.7% compared to that without iodine) and low electrical resistivity of 0.21 Omega.cm. The assembled symmetric supercapacitors, combined with dual redox-active electrolyte (Bi3+ and Br-), deliver the specific capacitance of 1216 F g(-1), energy density of 65.4 Wh kg(-1), as well as power density of 787.3Wkg(-1) at 2 A g(-1). In brief, the abundant biomass resource starch is exploited as carbon source, and the iodine sublimation reaction is conducted to provide more micropores to develop high-performance electrodes of supercapacitors. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

In this study, iodine was used as a pore-making agent to create hierarchically porous carbon with high specific surface area and low electrical resistivity for supercapacitor electrodes. By utilizing a dual redox-active electrolyte, the supercapacitors achieved high specific capacitance, energy density, and power density.