Biowaste-derived 3D honeycomb-like porous carbon with binary-heteroatom doping for high-performance flexible solid-state supercapacitors

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 6; no. 1; pp. 160 - 166
• Main Authors: Liu, Yuxi, Xiao, Zechuan, Liu, Yongchang, Fan, Li-Zhen
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2018
• Subjects: Capacitance; Carbonization; Doping; Electrodes; Electrolytes; Honeycomb construction; Ion storage; Nitrogen; Solid state; Sulfur; Supercapacitors
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C7TA09055B

Corncob sponge is a type of agricultural abandoned byproduct and abundant around the world. Herein, a facile one-pot carbonization and activation method is developed to convert corncob sponge into three-dimensional (3D) interconnected honeycomb-like porous carbon, followed by an effective binary-heteroatom doping to fabricate nitrogen and sulfur co-doped activated corncob sponge (denoted as N,S-ACS). The resultant products possess a high accessible surface area (1874 m 2 g −1 ) induced by the 3D honeycomb-like framework and a highly porous structure that benefits a large ion storage and a rapid ion transfer. In addition to the electrical double layer capacitance, heteroatom doping evokes faradic contribution. N,S-ACS demonstrates a remarkable specific capacitance of 404 and 253 F g −1 at the current densities of 0.1 and 10 A g −1 in a 6 mol L −1 KOH electrolyte, respectively, along with a high cycling stability with only 1% loss over 10 000 cycles. Furthermore, the assembled symmetric flexible solid-state supercapacitors with the electrode of N,S-ACS and the electrolyte of a PVA/KOH gel display a high integrated energy–power density of 30 W h kg −1 at 8 kW kg −1 and a 99% capacitance retention after 10 000 cycles at 3 A g −1 . The fascinating performance significantly endows N,S-ACS with great prospects as a supercapacitor electrode.