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A redox-flow battery with an alloxazine-based organic electrolyte


Redox-flow batteries (RFBs) can store large amounts of electrical energy from variable sources, such as solar and wind. Recently, redox-active organic molecules in aqueous RFBs have drawn substantial attention due to their rapid kinetics and low membrane crossover rates. Drawing inspiration from nature, here we report a high-performance aqueous RFB utilizing an organic redox compound, alloxazine, which is a tautomer of the isoalloxazine backbone of vitamin B2. It can be synthesized in high yield at room temperature by single-step coupling of inexpensive o-phenylenediamine derivatives and alloxan. The highly alkaline-soluble alloxazine 7/8-carboxylic acid produces a RFB exhibiting open-circuit voltage approaching 1.2 V and current efficiency and capacity retention exceeding 99.7% and 99.98% per cycle, respectively. Theoretical studies indicate that structural modification of alloxazine with electron-donating groups should allow further increases in battery voltage. As an aza-aromatic molecule that undergoes reversible redox cycling in aqueous electrolyte, alloxazine represents a class of radical-free redox-active organics for use in large-scale energy storage.

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Figure 1: Cyclic voltammogram and cell schematic.
Figure 2: Cell performance.
Figure 3: Theoretical calculation and cyclic voltammetry of alloxazines.


  1. Dunn, B., Kamath, H. & Tarascon, J.-M. Electrical energy storage for the grid: a battery of choices. Science 334, 928–935 (2011).

    Article  Google Scholar 

  2. Nguyen, T. & Savinell, R. F. Flow batteries. Electrochem. Soc. Interface 19, 54–56 (2010).

    Article  Google Scholar 

  3. Yang, Z. et al. Electrochemical energy storage for green grid. Chem. Rev. 111, 3577–3613 (2011).

    Article  Google Scholar 

  4. Biello, D. Solar wars. Sci. Am. 311, 66–71 (2014).

    Article  Google Scholar 

  5. Skyllas-Kazacos, M., Chakrabarti, M. H., Hajimolana, S. A., Mjalli, F. S. & Saleem, M. Progress in flow battery research and development. J. Electrochem. Soc. 158, R55–R79 (2011).

    Article  Google Scholar 

  6. Weber, A. Z. et al. Redox flow batteries: a review. J. Appl. Electrochem. 41, 1137–1164 (2011).

    Article  Google Scholar 

  7. Perry, M. L. & Weber, A. Z. Advanced redox-flow batteries: a perspective. J. Electrochem. Soc. 163, A5064–A5067 (2016).

    Article  Google Scholar 

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

    Article  Google Scholar 

  9. Huskinson, B., Marshak, M. P., Gerhardt, M. R. & Aziz, M. J. Cycling of a quinone-bromide flow battery for large-scale electrochemical energy storage. ECS Trans. 61, 27–30 (2014).

    Article  Google Scholar 

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

    Article  Google Scholar 

  11. Janoschka, T. et al. An aqueous, polymer-based redox-flow battery using non-corrosive, safe, and low-cost materials. Nature 527, 78–81 (2015).

    Article  Google Scholar 

  12. Schubert, U. S. et al. Polymer/zinc hybrid-flow battery using block copolymer micelles featuring a TEMPO corona as catholyte. Polym. Chem. 28, 2238–2243 (2016).

    Google Scholar 

  13. 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 (2015).

    Article  Google Scholar 

  14. Milstein, J. D., Liang, S., Liou, C., Badel, A. F. & Brushett, F. R. Voltammetry study of quinoxaline in aqueous electrolytes. Electrochim. Acta 180, 695–704 (2015).

    Article  Google Scholar 

  15. Brushett, F., Jansen, A. N., Vaughey, J. T. & Milshtein, J. D. Materials for use with aqueous redox flow batteries and related methods and systems. International Patent Application WO 2015/126907.

  16. Chen, S., Hossain, M. S. & Foss, F. W. Organocatalytic dakin oxidation by nucleophilic flavin catalysts. Org. Lett. 14, 2806–2809 (2012).

    Article  Google Scholar 

  17. de Gonzalo, G., Smit, C., Jin, J., Minnaard, A. J. & Fraaije, M. W. Turning a riboflavin-binding protein into a self-sufficient monooxygenase by cofactor redesign. Chem. Commun. 47, 11050–11052 (2011).

    Article  Google Scholar 

  18. Lindén, A. A., Johansson, M., Hermanns, N. & Bäckvall, J.-E. Efficient and selective sulfoxidation by hydrogen peroxide, using a recyclable flavin-[BMIm]PF6 catalytic system. J. Org. Chem. 71, 3849–3853 (2006).

    Article  Google Scholar 

  19. Hasford, J. J. & Rizzo, C. J. Linear free energy substituent effect on flavin redox chemistry. J. Am. Chem. Soc. 120, 2251–2255 (1998).

    Article  Google Scholar 

  20. Müller, F. in Radicals in Biochemistry (eds Boschke, F. L. et al.) 71–107 (Springer, 1983).

    Book  Google Scholar 

  21. Hong, J. et al. Biologically inspired pteridine redox centres for rechargeable batteries. Nature Commun. 5, 5335 (2014).

    Article  Google Scholar 

  22. Er, S., Suh, C., Marshak, M. P. & Aspuru-Guzik, A. Computational design of molecules for an all-quinone redox flow battery. Chem. Sci. 6, 885–893 (2015).

    Article  Google Scholar 

  23. Koziol, J. & Metzler, D. E. Formation and possible structure of covalent hydrates of alloxazines. Z. Naturforsch. B 27, 1027–1029 (2014).

    Article  Google Scholar 

  24. Surrey, A. R. & Nachod, F. C. Alkaline hydrolysis of riboflavin. J. Am. Chem. Soc. 73, 2336–2338 (1951).

    Article  Google Scholar 

  25. Ahmad, I., Rapson, H. D. C., Heelis, P. F. & Phillips, G. O. Alkaline hydrolysis of 7,8-dimethyl-10-(formylmethyl)isoalloxazine. A kinetic study. J. Org. Chem. 45, 731–733 (1980).

    Article  Google Scholar 

  26. Prukała, D. et al. Acid–base equilibriums of lumichrome and its 1-methyl, 3-methyl, and 1,3-dimethyl derivatives. J. Phys. Chem. A 116, 7474–7490 (2012).

    Article  Google Scholar 

  27. Koziol, J., Tyrakowska, B. & Müller, F. The structure of covalent hydrates of alloxazines. A reinvestigation. Helv. Chim. Acta 64, 1812–1817 (1981).

    Article  Google Scholar 

  28. O’Connor, C. Acidic and basic amide hydrolysis. Q. Rev. Chem. Soc. 24, 553–564 (1970).

    Article  Google Scholar 

  29. Liu, Q. H. et al. High performance vanadium redox flow batteries with optimized electrode configuration and membrane selection. J. Electrochem. Soc. 159, A1246–A1252 (2012).

    Article  Google Scholar 

  30. Li, X.-L. & Fu, Y. Theoretical study of reduction potentials of substituted flavins. J. Mol. Struct. THEOCHEM 856, 112–118 (2008).

    Article  Google Scholar 

  31. Gómez-Bombarelli, R., González-Pérez, M., Pérez-Prior, M. T., Calle, E. & Casado, J. Computational calculation of equilibrium constants: addition to carbonyl compounds. J. Phys. Chem. A 113, 11423–11428 (2009).

    Article  Google Scholar 

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This work was funded by the US DOE ARPA-E award no. DE-AR0000348, NSF no. NSF-CBET-1509041, the Massachusetts Clean Energy Technology Center, and the Harvard John A. Paulson School of Engineering and Applied Sciences. We thank C. Qian for designing the Fig. 1d scheme. We appreciate support from the Odyssey Cluster and Research Computing of Harvard University’s Faculty of Arts and Sciences.

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Authors and Affiliations



K.L., R.G.G. and M.J.A. formulated the project. K.L. and L.T. synthesized the compounds. K.L., E.S.B. and L.T. collected and analysed the NMR data. K.L., Q.C., E.S.B. and A.V. collected and analysed the electrochemical data. K.L. and A.V. measured solubility. R.G.-B. and A.A.-G. performed theoretical analysis. K.L., R.G.G. and M.J.A. wrote the paper, and all authors contributed to revising the paper.

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Correspondence to Michael J. Aziz or Roy G. Gordon.

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The authors declare no competing financial interests.

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Supplementary Information

Supplementary Figures 1–13, Supplementary Table 1–2. (PDF 946 kb)

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Lin, K., Gómez-Bombarelli, R., Beh, E. et al. A redox-flow battery with an alloxazine-based organic electrolyte. Nat Energy 1, 16102 (2016).

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