Interconnected and hierarchical porous carbon derived from soybean root for ultrahigh rate supercapacitors

Suffering from the stable intrinsic structure and strong cross-linking between cellulose, hemicellulose, and lignin, the strategy of directional editing of biomass pore structure is rare. Here, we develop a simple hydrothermal strategy to reconstruct the macroporous biomass precursor to obtain interconnected and hierarchical porous carbon. Benefiting from its interconnected and hierarchical micro/meso/macroporous structure, high mesopore ratio of 74%, large surface area of 2690 m(2) g(-1), and abundant surface heteroatom (O, N, S), the resulting carbon performs an ultrahigh capacitance of 328 F g(-1) at 1 A g(-1), outstanding rate performance with a high capacitance retention of 60% at 100 A g(-1), as well as good cycle stability in two-electrode system in 6 M KOH. Importantly, the resulting carbon also exhibits high areal capacitance of 4.1 F cm(-2) at 1 A g(-1) under a high mass loading of 20 mg cm(-2) due to the robust ion-transfer kinetics. Furthermore, superior energy densities of 46.7 Wh kg(-1) at 622 W kg(-1) and 25.8 Wh kg(-1) at 27.3 kW kg(-1) are achieved in neat EMIM BF4. (c) 2020 Elsevier B.V. All rights reserved.