Despite intense research in the field of aqueous organic redox flow batteries, low molecular stability of electroactive compounds limits further commercialization. Additionally, currently used methods typically cannot differentiate between individual capacity fade mechanisms, such as degradation of electroactive compound and its cross-over through the membrane. We present a more complex method for in situ evaluation of (electro)chemical stability of electrolytes using a flow electrolyser and a double half-cell including permeation measurements of electrolyte cross-over through a membrane by a UV-VIS spectrometer. The method is employed to study (electro)chemical stability of acidic negolyte based on an anthraquinone sulfonation mixture containing mainly 2,6- and 2,7-anthraquinone disulfonic acid isomers, which can be directly used as an RFB negolyte. The effect of electrolyte state of charge (SoC), current load and operating temperature on electrolyte stability is tested. The results show enhanced capacity decay for fully charged electrolyte (0.9 and 2.45% per day at 20 °C and 40 °C, respectively) while very good stability is observed at 50% SoC and lower, even at 40 °C and under current load (0.02% per day). HPLC analysis conformed deep degradation of AQ derivatives connected with the loss of aromaticity. The developed method can be adopted for stability evaluation of electrolytes of various organic and inorganic RFB chemistries.

Centre for Organic Chemistry Rybitvi 296 533 54 Rybitvi Czech Republic

Department of Chemical Engineering University of Chemistry and Technology Technická 5 Praha 6 166 28 Prague Czech Republic

New Technologies Research Centre University of West Bohemia Univerzitní 8 306 14 Plzeň Czech Republic

Synthesia a s Semtín 103 530 02 Pardubice Czech Republic

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Lourenssen K., Williams J., Ahmadpour F., Clemmer R., Tasnim S. Vanadium Redox Flow Batteries: A Comprehensive Review. J. Energy Storage. 2019;25:100844. doi: 10.1016/j.est.2019.100844. DOI

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. 2017;56:686–711. doi: 10.1002/anie.201604925. PubMed DOI PMC

Kwabi D.G., Lin K., Ji Y., Kerr E.F., Goulet M.-A., De Porcellinis D., Tabor D.P., Pollack D.A., Aspuru-Guzik A., Gordon R.G., et al. Alkaline Quinone Flow Battery with Long Lifetime at pH 12. Joule. 2018;2:1894–1906. doi: 10.1016/j.joule.2018.07.005. DOI

Lin K., Chen Q., Gerhardt M.R., Tong L., Kim S.B., Eisenach L., Valle A.W., Hardee D., Gordon R.G., Aziz M.J., et al. Alkaline Quinone Flow Battery. Science. 2015;349:1529–1532. doi: 10.1126/science.aab3033. PubMed DOI

Huskinson B., Marshak M.P., Suh C., Er S.S., Gerhardt M.R., Galvin C.J., Chen X., Aspuru-Guzik A., Gordon R.G., Aziz M.J. A Metal-Free Organic–Inorganic Aqueous Flow Battery. Nat. Cell Biol. 2014;505:195–198. doi: 10.1038/nature12909. PubMed DOI

Chen Q., Eisenach L., Aziz M.J. Cycling Analysis of a Quinone-Bromide Redox Flow Battery. J. Electrochem. Soc. 2015;163:A5057–A5063. doi: 10.1149/2.0081601jes. DOI

Chen Q., Gerhardt M.R., Hartle L., Aziz M.J. A Quinone-Bromide Flow Battery with 1 W/cm2 Power Density. J. Electrochem. Soc. 2015;163:A5010–A5013. doi: 10.1149/2.0021601jes. DOI

Gerhardt M.R., Rafael T., Gómez B., Chen Q., P M., Cooper M., Galvin J., Aspuru-Guzik A., G R., J G.M. Aziz Anthraquinone Derivatives in Aqueous Flow Batteries. Adv. Energy Mater. 2017;7:1601488. doi: 10.1002/aenm.201601488. DOI

Khataee A., Wedege K., Dražević E., Bentien A. Differential pH as a Method for Increasing Cell Potential in Organic Aqueous Flow Batteries. J. Mater. Chem. A. 2017;5:21875–21882. doi: 10.1039/C7TA04975G. DOI

Hu B., Luo J., Hu M., Yuan B., Liu T.L. A pH-Neutral, Metal-Free Aqueous Organic Redox Flow Battery Employing an Ammonium Anthraquinone Anolyte. Angew. Chem. 2019;58:16629–16636. doi: 10.1002/anie.201907934. PubMed DOI

Lee W., Permatasari A., Kwon Y. Neutral pH Aqueous redox Flow Batteries Using an Anthraquinone-Ferrocyanide Redox Couple. J. Mater. Chem. C. 2020;8:5727–5731. doi: 10.1039/D0TC00640H. DOI

Yang B., Murali A., Nirmalchandar A., Jayathilake B., Prakash G.K.S., Narayanan S.R. A Durable, Inexpensive and Scalable Redox Flow Battery Based on Iron Sulfate and Anthraquinone Disulfonic Acid. J. Electrochem. Soc. 2020;167:060520. doi: 10.1149/1945-7111/ab84f8. DOI

Hoober-Burkhardt L., Krishnamoorthy S., Yang B., Murali A., Nirmalchandar A., Prakash G.K.S., Narayanan S.R. A New Michael-Reaction-Resistant Benzoquinone for Aqueous Organic Redox Flow Batteries. J. Electrochem. Soc. 2017;164:A600–A607. doi: 10.1149/2.0351704jes. DOI

Tong L., Chen Q., Wong A.A., Gómez-Bombarelli R., Aspuru-Guzik A., Gordon R.G., Aziz M.J. UV–VIS Spectrophotometry of Quinone flow Battery Electrolyte for in Situ Monitoring and Improved Electrochemical Modeling of Potential and Quinhydrone Formation. Phys. Chem. Chem. Phys. 2017;19:31684–31691. doi: 10.1039/C7CP05881K. PubMed DOI

Carney T.J., Steven J., Collins J., Moore S., Fikile R. Brushett Concentration-Dependent Dimerization of Anthraquinone Disulfonic Acid and Its Impact on Charge Storage. Chem. Mater. 2017;29:4801–4810. doi: 10.1021/acs.chemmater.7b00616. DOI

Wiberg C., Carney T.J., Brushett F., Ahlberg E., Wang E. Dimerization of 9,10-anthraquinone-2,7-Disulfonic acid (AQDS) Electrochim. Acta. 2019;317:478–485. doi: 10.1016/j.electacta.2019.05.134. DOI

Wermeckes B., Beck F. Acid Catalyzed Disproportionation of Anthrahydroquinone to Anthraquinone and Anthrone. Denki Kagaku Oyobi Kogyo Butsuri Kagaku. 1994;62:1202–1205. doi: 10.5796/electrochemistry.62.1202. DOI

Goulet M.-A., Tong L., Pollack D.A., Tabor D.P., Odom S.A., Aspuru-Guzik A., Kwan E.E., Gordon R.G., Aziz M.J. Extending the Lifetime of Organic Flow Batteries via Redox State Management. J. Am. Chem. Soc. 2019;141:8014–8019. doi: 10.1021/jacs.8b13295. PubMed DOI

Goulet M.-A., Aziz M.J. Flow Battery Molecular Reactant Stability Determined by Symmetric Cell Cycling Methods. J. Electrochem. Soc. 2018;165:A1466–A1477. doi: 10.1149/2.0891807jes. DOI

Gerhardt M.R., Beh E.S., Tong L., Gordon R.G., Aziz M.J. Comparison of Capacity Retention Rates During Cycling of Quinone-Bromide Flow Batteries. MRS Adv. 2017;2:431–438. doi: 10.1557/adv.2016.667. DOI

Kwabi D.G., Wong A.A., Aziz M.J. Rational Evaluation and Cycle Life Improvement of Quinone-Based Aqueous Flow Batteries Guided by In-Line Optical Spectrophotometry. J. Electrochem. Soc. 2018;165:A1770–A1776. doi: 10.1149/2.0791809jes. DOI

Charvát J., Mazúra P., Dundáleka J., Pocedič J., Vrána J., Mrlík J., Kosek J., Dinter S. Performance Enhancement of Vanadium Redox flow Battery by Optimized Electrode Compression and Operational Conditions. J. Energy Storage. 2020;30:101468. doi: 10.1016/j.est.2020.101468. DOI

Derr I., Bruns M., Langner J., Fetyan A., Melke J., Roth C. Degradation of all-Vanadium Redox flow Batteries (VRFB) Investigated by Electrochemical Impedance and X-ray Photoe-Lectron Spectroscopy: Part 2 Electrochemical Degradation. J. Power Sources. 2016;325:351–359. doi: 10.1016/j.jpowsour.2016.06.040. DOI

Derr I., Przyrembel D., Schweer J., Fetyan A., Langner J., Melke J., Weinelt M., Roth C. Electroless Chemical Aging of Carbon Felt Electrodes for the All-Vanadium Redox Flow Battery (VRFB) Investigated by Electrochemical Impedance and X-Ray Photoelectron Spectroscopy. Electrochim. Acta. 2017;246:783–793. doi: 10.1016/j.electacta.2017.06.050. DOI

Mazur P., Mrlik J., Pocedic J., Vrana J., Dundalek J., Kosek J., Bystron T. Effect of Graphite Felt Properties on the Long-Term Durability of Negative Electrode in Vanadium Redox Flow Battery. J. Power Sources. 2019;414:354–365. doi: 10.1016/j.jpowsour.2019.01.019. DOI

Family Tree for Aqueous Organic Redox Couples for Redox Flow Battery Electrolytes: A Conceptual Review