Disulfide Bonds Reinforced Self-Assembly of Cellulosic Wastes Toward N/S-Enriched 3D Carbon Foams with Starfish-Like Networks for High-Performance Supercapacitors.

Developing high-performance electrodes derived from cellulosic wastes is an effective strategy for promoting large-scale energy storage and achieving carbon neutrality, yet how to enhance capacitive activity from the perspective of surface-interface structure regulation remains a challenge. Herein, a disulfide bond reinforced self-assembly of cellulosic wastes strategy is demostrated to fabricate 3D carbon foams with thiram and bio-straws as examples. The cellulose-enriched piths of straws (EP) are impregnated with thiram solution followed by pyrolysis, where thiram can form a stable 3D cross-linked networks via disulfide-centered hydrogen bonds reinforced self-assembly of EP and thiram, endowing the obtained starfish-like skeleton connected 3D carbon foams with high N/S contents and hierarchical porous structure. Consequently, The resultant EPCF-800 as a binder-free and conductive agent-free electrode achieves an ultrahigh specific capacitance of 342 F g^-1 in aqueous electrolyte at 0.5 A g^-1, meanwhile, DFT calculations reveal that the high-level N/S-doping can effectively weaken the adsorption barriers of K-ions. Moreover, the EPCF-800 assembles flexible solid-state supercapacitors delivering a high energy density of 30.11 Wh kg^-1 and a long cycle-life. This work will shed light on the value-added utilization of cellulosic wastes from surface-interface engineering and molecular chemical engineering to pave the way for fabricating high-performance supercapacitors.