能源化学(英文版)

能源化学(英文) ›› 2019, Vol. 28 ›› Issue (7): 52-56.DOI: 10.1016/j.jechem.2018.09.020

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A bipolar verdazyl radical for a symmetric all-organic redox flow-type battery

Grant D. Charltona, Stephanie M. Barbonb, Joe B. Gilroyb, C. Adam Dykera   

  1. a Department of Chemistry, University of New Brunswick, Fredericton E3B 5A3, New Brunswick, Canada;
    b Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research(CAMBR), The University of Western Ontario, London N6A 5B7, Ontario, Canada
  • 收稿日期:2018-08-29 修回日期:2018-09-27 出版日期:2019-07-15 发布日期:2019-07-15
  • 通讯作者: Joe B. Gilroy, C. Adam Dyker
  • 基金资助:
    This work was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada (C. A. D.:DG, 04279; J. B. G.:DG, 435675 and S. M. B.:CGS D scholarship).

A bipolar verdazyl radical for a symmetric all-organic redox flow-type battery

Grant D. Charltona, Stephanie M. Barbonb, Joe B. Gilroyb, C. Adam Dykera   

  1. a Department of Chemistry, University of New Brunswick, Fredericton E3B 5A3, New Brunswick, Canada;
    b Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research(CAMBR), The University of Western Ontario, London N6A 5B7, Ontario, Canada
  • Received:2018-08-29 Revised:2018-09-27 Online:2019-07-15 Published:2019-07-15
  • Contact: Joe B. Gilroy, C. Adam Dyker
  • Supported by:
    This work was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada (C. A. D.:DG, 04279; J. B. G.:DG, 435675 and S. M. B.:CGS D scholarship).

摘要： A symmetric all-organic non-aqueous redox flow-type battery was investigated employing the neutral small molecule radical 3-phenyl-1,5-di-p-tolylverdazyl, which can be reversibly oxidized and reduced in one-electron processes, as the sole charge storage material. Cyclic voltammetry of the verdazyl radical in 0.5 M tetrabutylammonium hexafluorophosphate (TBAPF6) in acetonitrile revealed redox couples at-0.17 V and-1.15 V vs. Ag+/Ag, leading to a theoretical cell voltage of 0.98 V. From the dependence of peak currents on the square root of the scan rate, diffusion coefficients on the order of 4×10-6 cm2 s-1 were demonstrated. Cycling performance was assessed in a static cell employing a Tokoyuma AHA anion exchange membrane, with 0.04 M verdazyl as catholyte and anolyte in 0.5 M TBAPF6 in acetonitrile at a current density of 0.12 mA cm-2. Although coulombic efficiencies were good (94%-97%) throughout the experiment, the capacity faded gradually from high initial values of 93% of the theoretical discharge capacity to 35% by the 50th cycle. Voltage and energy efficiencies were 68% and 65%, respectively. Postcycling analysis by cyclic voltammetry revealed that decomposition of the active material with cycling is a leading cause of cell degradation.

关键词: All-organic redox flow battery, Energy storage, Verdazyl radicals, Organic radical, Coin cell

Abstract: A symmetric all-organic non-aqueous redox flow-type battery was investigated employing the neutral small molecule radical 3-phenyl-1,5-di-p-tolylverdazyl, which can be reversibly oxidized and reduced in one-electron processes, as the sole charge storage material. Cyclic voltammetry of the verdazyl radical in 0.5 M tetrabutylammonium hexafluorophosphate (TBAPF6) in acetonitrile revealed redox couples at-0.17 V and-1.15 V vs. Ag+/Ag, leading to a theoretical cell voltage of 0.98 V. From the dependence of peak currents on the square root of the scan rate, diffusion coefficients on the order of 4×10-6 cm2 s-1 were demonstrated. Cycling performance was assessed in a static cell employing a Tokoyuma AHA anion exchange membrane, with 0.04 M verdazyl as catholyte and anolyte in 0.5 M TBAPF6 in acetonitrile at a current density of 0.12 mA cm-2. Although coulombic efficiencies were good (94%-97%) throughout the experiment, the capacity faded gradually from high initial values of 93% of the theoretical discharge capacity to 35% by the 50th cycle. Voltage and energy efficiencies were 68% and 65%, respectively. Postcycling analysis by cyclic voltammetry revealed that decomposition of the active material with cycling is a leading cause of cell degradation.

Key words: All-organic redox flow battery, Energy storage, Verdazyl radicals, Organic radical, Coin cell