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Indole-based conjugated macromolecules as a redox-mediated electrolyte for an ultrahigh power supercapacitor
Energy & Environmental Science ( IF 32.5 ) Pub Date : 2017-10-06 00:00:00 , DOI: 10.1039/c7ee02584j
Ting Xiong 1, 2, 3, 4, 5 , Wee Siang Vincent Lee 1, 2, 3, 4 , Li Chen 6, 7, 8, 9 , Teck Leong Tan 4, 10, 11, 12, 13 , Xiaolei Huang 1, 2, 3, 4 , Junmin Xue 1, 2, 3, 4
Affiliation  

Balancing energy density and power density has been a critical challenge since the inception of supercapacitors. Introducing redox-active additives in the supporting electrolyte has been shown to increase the energy density, however the power density and cycling stability are severely hampered in the process. Herein, an extensively conjugated indole-based macromolecule consisting of 5,6-dihydroxyindole/5,6-quinoneindole motifs, prepared by electrochemical polymerization of dopamine under acidic conditions, was employed as a redox-active additive. By utilizing the conjugation effect, the HOMO–LUMO gap (HLG) of the extensively conjugated indole-based macromolecule was reduced to ca. 2.08 eV, which enhanced the electronic transfer kinetics, in turn improving the power density and reversibility of redox reactions. When coupled with a porous honeycomb-like carbon (PHC) electrode, the assembled supercapacitor delivered an excellent rate performance with a high specific capacitance of 205 F g−1 at 1000 A g−1. This work reports one of the highest power densities recorded at 153 kW kg−1 for redox-mediated electrolyte systems with a respectable energy density of 8.8 W h kg−1. In addition to an excellent cycling stability of 97.1% capacitance retention after 20 000 charge/discharge cycles, the conjugation degree has to be considered when engineering the redox-active electrolyte so as to improve the power density and stability.

中文翻译:

基于吲哚的共轭大分子作为氧化还原介导的超高功率超级电容器的电解质

自从超级电容器问世以来,平衡能量密度和功率密度一直是一个严峻的挑战。已显示在支持电解质中引入氧化还原活性添加剂可增加能量密度,但是在此过程中严重阻碍了功率密度和循环稳定性。本文中,由多巴胺在酸性条件下的电化学聚合制备的由5,6-二羟基吲哚/ 5,6-醌吲哚基序组成的广泛共轭的基于吲哚的大分子用作氧化还原活性添加剂。通过利用共轭效应,广泛共轭的基于吲哚的大分子的HOMO-LUMO间隙(HLG)减小到了约。2.08 eV增强了电子转移动力学,进而提高了功率密度和氧化还原反应的可逆性。当与多孔蜂窝状碳(PHC)电极耦合时,组装的超级电容器在1000 A g -1下具有205 F g -1的高比电容,具有出色的倍率性能。这项工作报告了氧化还原介导的电解质系统在153 kW kg -1时记录的最高功率密度之一,可观的能量密度为8.8 W h kg -1。除了在20 000次充电/放电循环后具有97.1%的电容保持率的出色循环稳定性外,在设计氧化还原活性电解质时还必须考虑共轭度,以提高功率密度和稳定性。
更新日期:2017-10-16
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