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Title: Radical Compatibility with Nonaqueous Electrolytes and Its Impact on an All-Organic Redox Flow Battery

Nonaqueous redox flow batteries hold the promise to achieve higher energy density ascribed to the broader voltage window than their aqueous counterparts, but their current performance is limited by low redox material concentration, poor cell efficiency, and inferior cycling stability. We report a new nonaqueous total-organic flow battery based on high concentrations of 9-fluorenone as negative and 2,5-di-tert-butyl-1-methoxy-4-[2’-methoxyethoxy]benzene as positive redox materials. The supporting electrolytes are found to greatly affect the cycling stability of flow cells through varying chemical stabilities of the charged radical species, especially the 9-fluorenone radical anions, as confirmed by electron spin resonance. Such an electrolyte optimization sheds light on mechanistic understandings of capacity fading in flow batteries employing organic radical-based redox materials and demonstrates that rational design of supporting electrolyte is vital for stable cyclability.
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Publication Date:
OSTI Identifier:
Report Number(s):
48374; TE1400000; KC0208010
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Angewandte Chemie International Edition, 127(30):8808-8811
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
Environmental Molecular Sciences Laboratory