From salt-filled ZIF-8 to open-door nanoporous carbon with optimized pore system for electrochemical supercapacitor with enhanced energy density. (July 2022)

• Record Type: Journal Article
• Authors: Xue, Chunfeng; Zhao, Wei; Zhang, Qian; Wang, Jinxin; Wei, Yueyue; Lv, Kai; Wu, Teng; Lin, Yu; Li, Xiaohong; Hao, Xiaogang
• Is Part Of: Journal of energy storage. Volume 51(2022)
• Publication Date: 2022-07
• Subjects: ZIF-8 -- Open structure -- NaCl -- Energy density -- Doped carbon; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2022.104421
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Zeolitic imidazolate framework (ZIF) derived carbon generally suffers from a hydrophobic close-ended microstructure, leading to poor rate capability and low energy density in supercapacitors. In view of the defects, a facile strategy is demonstrated to synthesize open-door nanoporous carbon with self-doped heteroatoms by the pyrolysis of salt-filled ZIF-8. Specifically, inert NaCl is impregnated into the channels of ZIF-8 to inhibit framework shrinkage and promote the generation of open pore system. The resultant carbon CZ-900 features with O, N co-doped surface and specific surface area of 1420 m 2 ·g −1 . It exhibits a specific capacitance of 574.9 F·g −1 at 0.5 A·g −1 in aqueous electrolyte of 1.0 M H2 SO4, which is higher than other carbons derived from ZIF-8. In the two-electrode system, it shows a high energy density up to 21.1 Wh·kg −1 at a power density of 211.3 W·kg −1 . The superior performances can be attributed to its integration of open-pore structure and N/O co-doped surface, which provides a fast ion-transport pathway, improved interface wettability, broadened operation potential and efficient faradic-activity. Highlights: Open-door porous carbon with doped surface is obtained by pyrolyzing salt-filled ZIF-8. The filled NaCl promotes the generation of open pore and inhibits framework shrinkage. The electrode based on carbon CZ-900 shows a specific capacitance of 574.9 F·g −1 at 0.5 A·g −1 in H2 SO4 . Carbon CZ-900 based symmetrical supercapacitor shows a high energy density 21.1 Wh·kg −1 .