A low dose KOH activation method is used to prepare starch-based porous carbon for high performance supercapacitors

Starch is a natural polysaccharide compound, second only to cellulose in natural abundance, with advantages such as a regular structure, high carbon content, and renewability. Developing high-performance, cost-effective, and sustainable electrode materials represents a significant challenge for starch-based supercapacitors. Therefore, this study eliminates the high cost associated with the traditional high-dose KOH activation process by employing a combined approach of pre‑carbonization and low-dose KOH activation to produce interconnected honeycomb-like porous carbon. Rational pre‑carbonization treatment fractures starch macromolecules, and the migration, rearrangement, and cross-linking of carbon atoms result in a loosened structure that facilitates uniform absorption of low doses KOH. The resulting interconnected porous carbon network possesses a reasonable mesopore volume and specific surface area, exhibiting an ultrahigh capacitance of 346 F g^-1 at 1 A g^-1 and a capacitance retention rate of 64 % at 80 A g^-1. In the assembled symmetric supercapacitors, the energy density reaches up to 9.2 Wh kg^-1 at a power density of 250 W kg^-1. The low-dose KOH activation method proposed in this study offers a viable pathway for commercializing starch-based porous carbon supercapacitors with high energy density.