TY - JOUR
T1 - Reversible Reduction of the TEMPO Radical
T2 - One Step Closer to an All-Organic Redox Flow Battery
AU - Wylie, Luke
AU - Blesch, Thomas
AU - Freeman, Rebecca
AU - Hatakeyama-Sato, Kan
AU - Oyaizu, Kenichi
AU - Yoshizawa-Fujita, Masahiro
AU - Izgorodina, Ekaterina I.
N1 - Funding Information:
The authors acknowledge a generous allocation of computer resources through the National Computational Infrastructure and the Monash eResearch Centre. This work was generously supported by the Australian Research Council through a Discovery Project Grant and a Future Fellowship for E.I. I and a Research Training Program scholarship for Luke Wylie.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/12/14
Y1 - 2020/12/14
N2 - Nitroxide radicals are considered as ideal redox species in all-organic redox flow batteries due to their redox potential of ∼2 V. These radicals are predominantly used in their polymerized form as cathode materials to a high efficiency. Attempts to use poly(nitroxide)s as anode materials have been unsuccessful due to irreversibility of the reduction process as the reduced form of a nitroxide undergoes a fast, irreversible proton transfer with an electrolyte. In this study, reduction of the nitroxide radical, TEMPO, was shown to become reversible in an ionic liquid. A redox potential of 2.5 V was achieved, with the reduction reversibility being maintained after 200 cycles. A fabricated symmetric electrochemical cell demonstrated a high coulombic efficiency of 60% over an extended period of time. This is the first report demonstrating a high degree of reversibility of nitroxide reduction, thus leading to a paradigm shift in the future design of redox flow batteries.
AB - Nitroxide radicals are considered as ideal redox species in all-organic redox flow batteries due to their redox potential of ∼2 V. These radicals are predominantly used in their polymerized form as cathode materials to a high efficiency. Attempts to use poly(nitroxide)s as anode materials have been unsuccessful due to irreversibility of the reduction process as the reduced form of a nitroxide undergoes a fast, irreversible proton transfer with an electrolyte. In this study, reduction of the nitroxide radical, TEMPO, was shown to become reversible in an ionic liquid. A redox potential of 2.5 V was achieved, with the reduction reversibility being maintained after 200 cycles. A fabricated symmetric electrochemical cell demonstrated a high coulombic efficiency of 60% over an extended period of time. This is the first report demonstrating a high degree of reversibility of nitroxide reduction, thus leading to a paradigm shift in the future design of redox flow batteries.
KW - cyclic voltammetry
KW - ionic liquids
KW - nitroxide radicals
KW - organic radical batteries
KW - stabilization
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U2 - 10.1021/acssuschemeng.0c05687
DO - 10.1021/acssuschemeng.0c05687
M3 - Article
AN - SCOPUS:85097785992
SN - 2168-0485
VL - 8
SP - 17988
EP - 17996
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
IS - 49
ER -