Theoretical exploration of 2,2′-bipyridines as electro-active compounds in flow batteries

Nonaqueous redox flow batteries are a promising technology for grid-scale energy storage, however, their commercial success relies on identifying redox active materials that exhibit extreme potentials, high solubilities in all states of charge, and long cycling stabilities. Meeting these requirements has been particularly challenging for molecules capable of storing negative charge. Within this context, the symmetric tetrazines remain unexplored despite their unique structural properties that enable them to meet these challenges. Herein, we prepared s-tetrazines substituted with methyl, methoxy, and thiomethyl substituents and evaluated their electrochemical properties, solubility, and cycling stability. These studies revealed that 3,6-dimethoxy-s-tetrazine undergoes a reversible one-electron reduction to generate a soluble (>0.5 M in electrolyte/solvent) and stable (t1/2 > 1240 h) radical anion. When implemented in a lab-scale flow battery, it exhibited a relatively slow capacity fade of 13% over 100 cycles (38 h). Given their uncommonly high solubility and cycling stability, we believe that s-tetrazine derivatives should be further explored for non-aqueous redox flow batteries.

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Aqueous Redox Flow Batteries: How ‘Green’ are the Redox Active Materials?

Green Chemistry ◽

10.1039/d1gc01333e ◽

2021 ◽

Author(s):

Zachary Deller ◽

Lathe A Jones ◽

Subashani Maniam

Keyword(s):

Solar Wind ◽

Renewable Energy ◽

Energy Storage ◽

Energy Industry ◽

Active Materials ◽

Redox Flow Batteries ◽

Redox Active ◽

Flow Batteries ◽

Renewable Energy Industry

Energy storage using aqueous organic redox flow batteries (ORFBs) is gaining momentum in recent years parallel with the renewable energy industry, principally to store energy from solar, wind and hydro...

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Redox-active poly(ionic liquid)s as active materials for energy storage applications

Journal of Materials Chemistry A ◽

10.1039/c6ta10056b ◽

2017 ◽

Vol 5 (31) ◽

pp. 16231-16240 ◽

Cited By ~ 35

Author(s):

G. Hernández ◽

M. Işik ◽

D. Mantione ◽

A. Pendashteh ◽

P. Navalpotro ◽

...

Keyword(s):

Ionic Liquid ◽

Energy Storage ◽

Lithium Metal ◽

Active Materials ◽

Redox Flow Batteries ◽

Redox Active ◽

Flow Batteries ◽

Energy Storage Applications ◽

Poly Ionic Liquid ◽

Storage Technologies

The incorporation of redox-active counter anions (anthraquinone and nitroxide groups) into poly(ionic liquid)s broadens the scope of applications to different energy storage technologies such as lithium, metal-air or redox-flow batteries.

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Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

10.26434/chemrxiv.7995935.v2 ◽

2019 ◽

Author(s):

Mariano Sánchez-Castellanos ◽

Martha M. Flores-Leonar ◽

Zaahel Mata-Pinzón ◽

Humberto G. Laguna ◽

Karl García-Ruiz ◽

...

Keyword(s):

Redox Potential ◽

Active Material ◽

Chemical Properties ◽

Small Subset ◽

Solubility In Water ◽

Protonation Reaction ◽

Redox Active ◽

Physico Chemical ◽

Pka Value ◽

Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

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Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

10.26434/chemrxiv.7995935 ◽

2019 ◽

Author(s):

Mariano Sánchez-Castellanos ◽

Martha M. Flores-Leonar ◽

Zaahel Mata-Pinzón ◽

Humberto G. Laguna ◽

Karl García-Ruiz ◽

...

Keyword(s):

Redox Potential ◽

Active Material ◽

Chemical Properties ◽

Small Subset ◽

Solubility In Water ◽

Protonation Reaction ◽

Redox Active ◽

Physico Chemical ◽

Pka Value ◽

Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

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