Wrinkled lamellar-like-structure activated carbon from distillers' grains for high-performance supercapacitors

A novel activated carbon material with a wrinkled lamellar-like structure (TCDG) was synthesized from distillers' grains (DG). In this work, calcium acetate was employed as a templating agent to construct a hierarchical layered architecture, effectively modulating the spatial arrangement of protein, fiber, and other components within the precursor. The resulting TCDG samples exhibited a distinct wrinkled lamellar morphology and a high specific surface area of 607.9 m² g^-1, which directly enhanced their electrochemical performance in supercapacitors. Specifically, the TCDG electrode delivered a specific capacitance of 415 F g^-1 at 0.5 A g^-1 in 6 M KOH electrolyte. The symmetric coin-type supercapacitor (SSC) devices based on the prepared TCDG-2 using 6 M KOH electrolyte can deliver high specific energy of 19.26 Wh kg^-1 at a specific power of 649.76 W kg^-1. Impressively, when the electrolyte solution was replaced with 3.21 M [BMIM]PF₆/NMP, the SSC devices performance improved significantly, achieving 49.54 Wh kg^-1 and 2977.75 W kg^-1. Moreover, the capacitance retains 91.7 % and the coulomb efficiency remains 99.0 % after 10,000 cycles tested at 10 A g^-1. High-quality sustainable carbon sources for electrode materials and expansion of carbon material sources can be achieved through this conclusion; meanwhile, it increases the added value of distiller's grains in the liquor industry, encourages high-value utilization of agricultural waste.