Understanding and Mitigating Capacity Fade in Aqueous Organic Redox Flow Batteries

Abstract

The use of water-soluble organic redox couples is a new and attractive pathway to a sustainable electrical energy storage system with the potential to be inexpensive and environmentally-friendly.[1][2][3] Further, several modifications of this type of redox flow battery arrangement using inorganic materials in combination with organic redox couples have also become the subject of research. [4][5] We have demonstrated the repeated cycling of a redox flow cell based on water-soluble organic redox couples (ORBAT) at high voltage efficiency, coulombic efficiency and power density. Recently, we presented for the first time the synthesis, characterization and properties of 3,6-dihydroxy-2,4-dimethylbenzenesulfonic acid (DHDMBS) as a new positive side electrolyte material for aqueous organic redox flow batteries (ORBAT). [6] DHDMBS overcame the major issue of the Michael reaction with water faced with previously reported positive electrolyte materials such as 4,5-dihydroxybenzene-1,3-disulfonic acid (BQDS) and other unsubstituted benzoquinones. The present study focuses on the crossover of DHDMBS from the positive side of the cell to the negative side. Specifically, we have explored various approaches to mitigate the effects of crossover. These approaches include low-permeability membranes, a new symmetric cell configuration using mixed electrolytes, and operating protocols that involve polarity switching. These approaches were found to reduce fade rates by 70% - 85%. We also uncover mechanistic pathways that lead to slow chemical modification that cause capacity to decrease under strongly acidic conditions during long-term cycling. The new understanding and methods presented here will contribute towards the development of ORBAT as an inexpensive and sustainable solution for large-scale electrical energy storage. Acknowledgement The Authors acknowledge the financial support for this research from ARPA-E Open-FOA program (DE-AR0000337), the University of Southern California, and the Loker Hydrocarbon Research [1] B. Yang, L. Hoober-Burkhardt, F. Wang, G. K. Surya Prakash, and S. R. Narayanan, “An Inexpensive Aqueous Flow Battery for Large-Scale Electrical Energy Storage Based on Water-Soluble Organic Redox Couples,” J. Electrochem. Soc., vol. 161, no. 9, pp. A1371–A1380, 2014. [2] B. Yang, L. Hoober-Burkhardt, S. Krishnamoorthy, A. Murali, G. K. S. Prakash, and S. R. Narayanan, “High-Performance Aqueous Organic Flow Battery with Quinone-Based Redox Couples at Both Electrodes,” J. Electrochem. Soc., vol. 163, no. 7, pp. A1442–A1449, 2016. [3] B. Huskinson, M. P. Marshak, C. Suh, S. Er, M. R. Gerhardt, C. J. Galvin, X. Chen, A. Aspuru-Guzik, R. G. Gordon, and M. J. Aziz, “A metal-free organic–inorganic aqueous flow battery,” Nature, vol. 505, no. 7482, pp. 195–198, 2014. [4] E. S. Beh, D. De Porcellinis, R. L. Gracia, K. T. Xia, R. G. Gordon, and M. J. Aziz, “A Neutral pH Aqueous Organic–Organometallic Redox Flow Battery with Extremely High Capacity Retention,” ACS Energy Lett., vol. 2, no. 3, pp. 639–644, 2017. [5] B. Hu, C. DeBruler, Z. Rhodes, and T. L. Liu, “Long-Cycling Aqueous Organic Redox Flow Battery (AORFB) toward Sustainable and Safe Energy Storage,” J. Am. Chem. Soc., vol. 139, no. 3, pp. 1207–1214, 2017. [6] L. Hoober-Burkhardt, S. Krishnamoorthy, B. Yang, A. Murali, A. Nirmalchandar, G. K. S. Prakash, and S. R. Narayanan, “A New Michael-Reaction-Resistant Benzoquinone for Aqueous Organic Redox Flow Batteries,” J. Electrochem. Soc., vol. 164, no. 4, pp. A600–A607, 2017. Figure 1

An All-Organic Aqueous Battery Powered by Adsorbed Quinone

“…This behavior agrees with previous studies, which attributed the phenomenon to the Michael addition of hydroxyl groups to Tiron. 26 Oxidized Tiron (o-benzoquinone disulfonate) can undergo nucleophilic attacks by water (Figure S2). 17 The process installs an additional hydroxyl group and converts the carbonyls back to hydroxyls.…”

The effect of plasma treated carbon felt on the performance of aqueous quinone‐based redox flow batteries

“…Once TironA is formed, desirable two‐electron redox reaction can occur and, from the second cycle, desirable reaction enabling the stable and reproducible charge and discharge step of QRFB takes place. This TironA can be effectively formed by activation process that is already reported 24‐28 . However, it is known that the electron transfer rate of TironA is still lower than that of AQDS.…”

“…This TironA can be effectively formed by activation process that is already reported. [24][25][26][27][28] However, it is known that the electron transfer rate of TironA is still lower than that of AQDS.…”

“…In this study, TironA and AQDS are used as redox couple for the operation of QRFBs because of their high solubility and good reversibility in acidic condition with two electrons involved redox reaction. The chemical structure of Tiron is then transformed into desirable 2,4,5,6‐tetrahydroxybenzene‐1,3‐disulfonic acid (TironA) by Michael addition reaction occurring during the first cycle of QRFB 24‐28 . Once TironA is formed, a desirable redox reaction occurs and the stable and reproducible charge and discharge steps of QRFB are continued from the second cycle 24 .…”

“…The chemical structure of Tiron is then transformed into desirable 2,4,5,6-tetrahydroxybenzene-1,3-disulfonic acid (TironA) by Michael addition reaction occurring during the first cycle of QRFB. [24][25][26][27][28] Once TironA is formed, a desirable redox reaction occurs and the stable and reproducible charge and discharge steps of QRFB are continued from the second cycle. 24 In spite of that, the electron transfer rate of TironA is still low, and the performance of QRFB using TironA, especially the voltage and energy efficiencies (VE and EE).…”