Redox-active organic molecules functionalized nitrogen-doped porous carbon derived from metal-organic framework as electrode materials for supercapacitor

• Published in: Electrochimica acta 2017-01, Vol.223, p.74-84
• Main Authors: Guo, Bingshu, Yang, Yuying, Hu, Zhongai, An, Yufeng, Zhang, Quancai, Yang, Xia, Wang, Xiaotong, Wu, Hongying
• Format: Article
• Language: English
• Subjects: Anchors; Asymmetrical supercapacitor; Batteries; Beryllium; Capacitance; Carbon; Diffusion layers; Electrode materials; Electrodes; Energy storage; Flux density; Metal-organic frameworks; Non-covalent functionalization; Organic chemistry; Organic molecules; Porosity; Porous materials; Rate capability; Specific surface; Supercapacitors; Zinc
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.12.012

•MOFs-derived porous carbon was non-covalently functionalized by organic molecules.•Resultant materials collect merits of MOFs carbon and organic molecule at once.•Positive and negative reactions take place in the large potential difference.•Negative and positive electrodes can generate potential self-matching behavior.•As-fabricated all-carbon asymmetric supercapacitor delivers higher energy density. Metal-organic frameworks (MOFs) have been turned out to be an excellently self-sacrificing template for preparing porous carbon. Herein, we synthesized a nitrogen-doped porous carbon materials (NPCs) by direct thermolysis of zinc-based MOFs (ZIF-8). Fortunately, the NPCs with high specific surface area and abundant pore structure was suitable for using as conductive substrate to anchor organic molecules. Anthraquinone (AQ), 1, 4-naphthoquinone (NQ) and tetrachlorobenzoquinone (TCBQ) were selected to functionalize NPCs via noncovalent interactions, respectively. As a consequence, the multielectron redox centers possessed by AQ, NQ and TCBQ were implanted in the NPCs. More interestingly, the electrochemical rate-determining step for the functionalized NPCs was surface process rather than diffusion, which is similar to capacitive behavior of the electrical double layer. The functionalized NPCs revealed an enhanced overall capacitance (about 1.4 times higher than NPCs) because the electrochemical capacitance was superposed on the electrical double layer capacitance. Furthermore, the as-assembled asymmetrical supercapacitor (ASC) exhibited excellent energy storage performance. The topological structure of MOFs skeleton and the potential self-matching behavior between the positive and negative electrodes were responsible for high energy density (23.5Whkg−1 at 0.7kWkg−1, which is 1.54 times higher than that of NPCs symmetrical supercapacitor) of the device.