Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Modular dimerization of organic radicals for stable and dense flow battery catholyte

Nature Energy volume 8, pages 1109–1118 (2023)Cite this article

Subjects

Abstract

Aqueous organic redox flow batteries (AORFBs) hold promise for safe, sustainable and cost-effective grid energy storage. However, developing catholyte redox molecules with the desired stability, power and energy density remains challenging. In this study, we synthesized a class of ionic liquid-mimicking (2,2,6,6-tetramethylpiperidin-1-yl)oxyl dimers (i-TEMPODs) through a building-block assembly platform. By systematically investigating 21 i-TEMPOD derivatives, we uncovered the optimal size and charge properties that prevent membrane crossover and allow formation of a water-in-salt state. Leveraging these advances, we realized substantial improvements in AORFB performance using the optimum i-TEMPOD catholyte at 2 M concentration. These enhancements encompass several crucial metrics showcased across multiple experiments, including robust cycling stability without apparent capacity decay during 96 days of cycling, facile electrochemical kinetics with a high maximum power density of 0.325 W m−2 and a high full-cell energy density of 47.3 Wh l−1 in a capacity-balanced configuration. These molecular designs pave the way towards low-cost and scalable AORFBs.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: TEMPO molecular design for optimized permeability–capacity trade-off.
Fig. 2: Modular building-block assembly of i-TEMPODs.
Fig. 3: Key electrochemical and physiochemical metrics of i-TEMPODs.
Fig. 4: i-TEMPOD RFB cycling with a low-ionic-conductivity AMVN membrane.
Fig. 5: RFB power and cycling performance with a high-ionic-conductivity DSVN membrane.
Fig. 6: Key metrics of i-TEMPOD RFBs compared with the state of the art.

Similar content being viewed by others

Data availability

The data that support the findings of this study are available in the paper and its Supplementary Information.

References

  1. Sánchez-Díez, E. et al. Redox flow batteries: status and perspective towards sustainable stationary energy storage. J. Power Sources 481, 228804 (2021).

    Article  Google Scholar 

  2. Wadia, C., Albertus, P. & Srinivasan, V. Resource constraints on the battery energy storage potential for grid and transportation applications. J. Power Sources 196, 1593–1598 (2011).

    Article  Google Scholar 

  3. Winsberg, J., Hagemann, T., Janoschka, T., Hager, M. D. & Schubert, U. S. Redox-flow batteries: from metals to organic redox-active materials. Angew. Chem. Int. Ed. 56, 686–711 (2017).

    Article  Google Scholar 

  4. Singh, V., Kim, S., Kang, J. & Byon, H. R. Aqueous organic redox flow batteries. Nano Res. 12, 1988–2001 (2019).

    Article  Google Scholar 

  5. Luo, J., Hu, B., Hu, M., Zhao, Y. & Liu, T. L. Status and prospects of organic redox flow batteries toward sustainable energy storage. ACS Energy Lett. 4, 2220–2240 (2019).

    Article  Google Scholar 

  6. Zhang, L., Feng, R., Wang, W. & Yu, G. Emerging chemistries and molecular designs for flow batteries. Nat. Rev. Chem. 6, 524–543 (2022).

    Article  Google Scholar 

  7. Kwabi, D. G., Ji, Y. & Aziz, M. J. Electrolyte lifetime in aqueous organic redox flow batteries: a critical review. Chem. Rev. 120, 6467–6489 (2020).

    Article  Google Scholar 

  8. Brushett, F. R., Aziz, M. J. & Rodby, K. E. On lifetime and cost of redox-active organics for aqueous flow batteries. ACS Energy Lett. 5, 879–884 (2020).

    Article  Google Scholar 

  9. Huskinson, B. et al. A metal-free organic–inorganic aqueous flow battery. Nature 505, 195–198 (2014).

    Article  Google Scholar 

  10. Lin, K. et al. Alkaline quinone flow battery. Science 349, 1529–1532 (2015).

    Article  Google Scholar 

  11. Amini, K. et al. An extremely stable, highly soluble monosubstituted anthraquinone for aqueous redox flow batteries. Adv. Funct. Mater. 33, 2211338 (2023).

    Article  Google Scholar 

  12. Jing, Y. et al. In situ electrochemical recomposition of decomposed redox-active species in aqueous organic flow batteries. Nat. Chem. 14, 1103–1109 (2022).

    Article  Google Scholar 

  13. Huang, S. et al. Molecular engineering of dihydroxyanthraquinone-based electrolytes for high-capacity aqueous organic redox flow batteries. Nat. Commun. 13, 4746 (2022).

    Article  Google Scholar 

  14. Liu, T., Wei, X., Nie, Z., Sprenkle, V. & Wang, W. A total organic aqueous redox flow battery employing a low cost and sustainable methyl viologen anolyte and 4-HO-TEMPO catholyte. Adv. Energy Mater. 6, 1501449 (2016).

    Article  Google Scholar 

  15. DeBruler, C. et al. Designer two-electron storage viologen anolyte materials for neutral aqueous organic redox flow batteries. Chem 3, 961–978 (2017).

    Article  Google Scholar 

  16. Beh, E. S. et al. A neutral pH aqueous organic–organometallic redox flow battery with extremely high capacity retention. ACS Energy Lett. 2, 639–644 (2017).

    Article  Google Scholar 

  17. DeBruler, C., Hu, B., Moss, J., Luo, J. & Liu, T. L. A sulfonate-functionalized viologen enabling neutral cation exchange, aqueous organic redox flow batteries toward renewable energy storage. ACS Energy Lett. 3, 663–668 (2018).

    Article  Google Scholar 

  18. Jin, S. et al. Near neutral pH redox flow battery with low permeability and long-lifetime phosphonated viologen active species. Adv. Energy Mater. 10, 2000100 (2020).

    Article  Google Scholar 

  19. Lv, X. L. et al. Dextrosil-viologen: a robust and sustainable anolyte for aqueous organic redox flow batteries. ACS Energy Lett. 7, 2428–2434 (2022).

    Article  Google Scholar 

  20. Sullivan, P. T. et al. Viologen hydrothermal synthesis and structure–property relationships for redox flow battery optimization. Preprint at ChemRxiv (2022).

  21. Hollas, A. et al. A biomimetic high-capacity phenazine-based anolyte for aqueous organic redox flow batteries. Nat. Energy 3, 508–514 (2018).

    Article  Google Scholar 

  22. Pang, S., Wang, X., Wang, P. & Ji, Y. Biomimetic amino acid functionalized phenazine flow batteries with long lifetime at near-neutral pH. Angew. Chem. Int. Ed. 60, 5289–5298 (2021).

    Article  Google Scholar 

  23. Hu, B. et al. Improved radical stability of viologen anolytes in aqueous organic redox flow batteries. Chem. Commun. 54, 6871–6874 (2018).

    Article  Google Scholar 

  24. Janoschka, T., Martin, N., Hager, M. D. & Schubert, U. S. An aqueous redox-flow battery with high capacity and power: the TEMPTMA/MV system. Angew. Chem. Int. Ed. 55, 14427–14430 (2016).

    Article  Google Scholar 

  25. Nolte, O., Rohland, P., Ueberschaar, N., Hager, M. D. & Schubert, U. S. Stability of TMA-TEMPO-based aqueous electrolytes for redox-flow batteries. J. Power Sources 525, 230996 (2022).

    Article  Google Scholar 

  26. Liu, B., Tang, C. W., Jiang, H., Jia, G. & Zhao, T. Carboxyl-functionalized TEMPO catholyte enabling high-cycling-stability and high-energy-density aqueous organic redox flow batteries. ACS Sustain. Chem. Eng. 9, 6258–6265 (2021).

    Article  Google Scholar 

  27. Schubert, U. S. et al. Structural alterations on the TEMPO scaffold and their impact on the performance as active materials for redox flow batteries. Mater. Adv. 3, 4278–4288 (2022).

    Article  Google Scholar 

  28. Pan, M. et al. Reversible redox chemistry in pyrrolidinium-based TEMPO radical and extended viologen for high-voltage and long-life aqueous redox flow batteries. Adv. Energy Mater. 12, 2103478 (2022).

    Article  Google Scholar 

  29. Hu, B., Hu, M., Luo, J. & Liu, T. L. A stable, low permeable TEMPO catholyte for aqueous total organic redox flow batteries. Adv. Energy Mater. 12, 2102577 (2022).

    Article  Google Scholar 

  30. Liu, Y. et al. A long-lifetime all-organic aqueous flow battery utilizing TMAP-TEMPO radical. Chem 5, 1861–1870 (2019).

    Article  Google Scholar 

  31. Zhou, W. et al. Fundamental properties of TEMPO-based catholytes for aqueous redox flow batteries: effects of substituent groups and electrolytes on electrochemical properties, solubilities and battery performance. RSC Adv. 10, 21839–21844 (2020).

    Article  Google Scholar 

  32. Ohira, A., Funaki, T., Ishida, E., Kim, J. D. & Sato, Y. Redox-flow battery operating in neutral and acidic environments with multielectron-transfer-type viologen molecular assembly. ACS Appl. Energy Mater. 3, 4377–4383 (2020).

    Article  Google Scholar 

  33. Silva, W., Zanatta, M., Ferreira, A. S., Corvo, M. C. & Cabrita, E. J. Revisiting ionic liquid structure-property relationship: a critical analysis. Int. J. Mol. Sci. 21, 7745 (2020).

    Article  Google Scholar 

  34. Hayes, R., Warr, G. G. & Atkin, R. Structure and nanostructure in ionic liquids. Chem. Rev. 115, 6357–6426 (2015).

    Article  Google Scholar 

  35. Kühnel, R.-S., Reber, D. & Battaglia, C. Perspective—electrochemical stability of water-in-salt electrolytes. J. Electrochem. Soc. 167, 070544 (2020).

    Article  Google Scholar 

  36. McEldrew, M., Goodwin, Z. A. H., Kornyshev, A. A. & Bazant, M. Z. Theory of the double layer in water-in-salt electrolytes. J. Phys. Chem. Lett. 9, 5840–5846 (2018).

    Article  Google Scholar 

  37. Jaumaux, P. et al. Localized water-in-salt electrolyte for aqueous lithium-ion batteries. Angew. Chem. Int. Ed. 60, 19965–19973 (2021).

    Article  Google Scholar 

  38. Martins, V. L. & Torresi, R. M. Water-in-salt electrolytes for high voltage aqueous electrochemical energy storage devices. Curr. Opin. Electrochem. 21, 62–68 (2020).

    Article  Google Scholar 

  39. Perry, M. L., Rodby, K. E. & Brushett, F. R. Untapped potential: the need and opportunity for high-voltage aqueous redox flow batteries. ACS Energy Lett. 7, 659–667 (2022).

    Article  Google Scholar 

  40. Zhang, M. et al. Understanding the microscopic structure of a ‘water-in-salt’ lithium ion battery electrolyte probed with ultrafast IR spectroscopy. J. Phys. Chem. C. 124, 8594–8604 (2020).

    Article  Google Scholar 

  41. Mjalli, F. S., Naser, J., Jibril, B., Alizadeh, V. & Gano, Z. Tetrabutylammonium chloride based ionic liquid analogues and their physical properties. J. Chem. Eng. Data 59, 2242–2251 (2014).

    Article  Google Scholar 

  42. Feng, R. et al. Reversible ketone hydrogenation and dehydrogenation for aqueous organic redox flow batteries. Science 372, 836–840 (2021).

    Article  Google Scholar 

  43. Wu, M. et al. Extremely stable anthraquinone negolytes synthesized from common precursors. Chem 6, 1432–1442 (2020).

    Article  Google Scholar 

  44. Goulet, M.-A. & Aziz, M. J. Flow battery molecular reactant stability determined by symmetric cell cycling methods. J. Electrochem. Soc. 165, A1466–A1477 (2018).

    Article  Google Scholar 

  45. Luo, J. et al. Unprecedented capacity and stability of ammonium ferrocyanide catholyte in pH neutral aqueous redox flow batteries. Joule 3, 149–163 (2019).

    Article  Google Scholar 

  46. Li, X. et al. Symmetry-breaking design of an organic iron complex catholyte for a long cyclability aqueous organic redox flow battery. Nat. Energy 6, 873–881 (2021).

    Article  Google Scholar 

  47. Chen, Q. et al. Designer ferrocene catholyte for aqueous organic flow batteries. ChemSusChem 14, 1295–1301 (2021).

    Article  Google Scholar 

  48. Li, W., Fu, H. C., Zhao, Y., He, J. H. & Jin, S. 14.1% efficient monolithically integrated solar flow battery. Chem 4, 2644–2657 (2018).

    Article  Google Scholar 

Download references

Acknowledgements

D.F. acknowledges start-up funds from the University of Wisconsin–Madison, the WARF Accelerator Project (AP) and the Draper Technology Innovation Fund (TIF). P.T.S. thanks the Vice Chancellor for Research and Graduate Education (VCRGE) for support. D.F., S.J., W.L., C.-J.C. and H.-C.F. thank UW–Madison WARF Accelerator for an electrification challenge grant. C.-J.C. thanks the National Science and Technology Council (NSTC) in Taiwan (109-2917-I-564-010) for a postdoctoral fellowship. R.J. and D.M. were supported by the Department of Energy (DOE; award no. DE-SC0020419). The authors thank I. Guzei for assistance with the collection of single-crystal X-ray diffraction data. The Bruker Quazar APEX2 was purchased by the UW–Madison Department of Chemistry with a portion of a generous gift from P. J. Bender and M. M. Bender. The Bruker AVANCE 400 NMR spectrometer was supported by the NSF (grant no. CHE-1048642). The purchase of the Thermo Q Exactive Plus mass spectrometer in 2015 was funded by the NIH (award no. 1S10 OD020022-1) to the Department of Chemistry. We also thank J. Berry and his student, J. Harris, in the UW–Madison Department of Chemistry for equipment and support in FTIR measurements.

Author information

Author notes

  1. These authors contributed equally: Xiu-Liang Lv, Patrick T. Sullivan.

Authors and Affiliations

  1. Department of Materials Science and Engineering, University of Wisconsin–Madison, Madison, WI, USA

    Xiu-Liang Lv, Patrick T. Sullivan, Ryan Jacobs, Dane Morgan & Dawei Feng

  2. Department of Chemistry, University of Wisconsin–Madison, Madison, WI, USA

    Wenjie Li, Hui-Chun Fu, Chih-Jung Chen, Song Jin & Dawei Feng

Authors
  1. Xiu-Liang Lv
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Patrick T. Sullivan
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Wenjie Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Hui-Chun Fu
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Ryan Jacobs
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Chih-Jung Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Dane Morgan
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Song Jin
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Dawei Feng
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

P.T.S. and X.-L.L. contributed equally to this work. D.F., W.L., P.T.S. and X.-L.L. conceived the work. D.F., W.L., S.J. and D.M. directed the experiments. X.-L.L. performed material synthesis and structure verification. H.-C.F. and C.-J.C. conducted the battery experiments. P.T.S. and X.-L.L. performed the physical, electrochemical and battery characterization. R.J. performed the AIMD simulations. All authors discussed and analysed the data. P.T.S., W.L. and D.F. wrote and revised the manuscript.

Corresponding authors

Correspondence to Wenjie Li or Dawei Feng.

Ethics declarations

Competing interests

Wisconsin Alumni Research Foundation (WARF) has filed a US utility patent application (P210314US01) regarding the catholyte materials described in this paper with D.F., X.-L.L., P.T.S. and W.L. as inventors. D.F., X.-L.L., and P.T.S. have ownership stakes in Flux XII, which may profit from the results reported herein. The remaining authors declare no competing interests.

Peer review

Peer review information

Nature Energy thanks the anonymous reviewers for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Methods, Figs. 1–101 and Tables 1–14.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Lv, XL., Sullivan, P.T., Li, W. et al. Modular dimerization of organic radicals for stable and dense flow battery catholyte. Nat Energy 8, 1109–1118 (2023). https://doi.org/10.1038/s41560-023-01320-w

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41560-023-01320-w

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing