Synthesis of linear amylose-based porous carbon via low-dosage KOH activation for high-performance supercapacitors

The pursuit of high-energy-density carbon-derived supercapacitors continues to confront substantial material challenges, particularly regarding the rational design of electrode architectures. Herein, we systematically investigate biomass-derived porous carbons synthesized through a sustainable low-dosage KOH activation strategy, employing three distinct starch precursors: native corn starch, linear amylose, and amylopectin. Comprehensive characterization reveals critical structure-property relationships, where the amylose-derived carbon exhibits a highly disordered amorphous architecture with optimized hierarchical porosity, contrasting with the relatively ordered domains observed in corn starch and amylopectin derivatives. This structural superiority translates to exceptional electrochemical performance, demonstrating a remarkable gravimetric capacitance of 328 F g −1 at 1 A g −1 with outstanding rate capability (74 % retention at 50 A g −1 ) in 6 M KOH electrolyte. When configured as a symmetric supercapacitor, the material achieves an energy density of 8.1 Wh kg −1 at 250 W kg −1 while maintaining 98 % capacitance retention over 20,000 cycles - metrics that surpass most reported starch-derived carbons. This work establishes fundamental guidelines for tailoring biopolymer-derived carbons through precursor selection and activation control, offering new perspectives for sustainable energy storage solutions. • Developed a sustainable low-dosage KOH activation strategy for starch-derived porous carbons. • Revealed amylose-derived carbon's disordered amorphous structure with hierarchical porosity. • Achieved 328 F g −1 capacitance at 1 A g −1 and 74 % retention at 50 A g −1 in aqueous systems. • Demonstrated 8.1 Wh kg −1 energy density with 98 % capacitance retention over 20,000 cycles.