Efficient Charge Storage in Dual-Redox Electrochemical Capacitors through Reversible Counterion-Induced Solid Complexation

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• 作者：Brian Evanko ; Seung Joon Yoo ; Sang-Eun Chun ; Xingfeng Wang ; Xiulei Ji ; Shannon W. Boettcher ; Galen D. Stucky
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：138
• 期：30
• 页码：9373-9376
• 全文大小：320K
• 年卷期：0
• ISSN：1520-5126

文摘

The performance of redox-enhanced electrochemical capacitors (redox ECs) is substantially improved when oxidized catholyte (bromide) and reduced anolyte (viologen) are retained within the porous electrodes through reversible counterion-induced solid complexation. Investigation of the mechanism illustrates design principles and identifies pentyl viologen/bromide (PV/Br) as a new high-performance electrolyte. The symmetric PV/Br redox EC produces a specific energy of 48.5 W·h/kg_dry at 0.5 A/g_dry (0.44 kW/kg_dry) with 99.7% Coulombic efficiency, maintains stability over 10 000 cycles, and functions identically when operated with reversed polarity.