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Assessment methods and performance metrics for redox flow batteries

Nature Energy volume 6, pages 582–588 (2021)Cite this article

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Abstract

Redox flow batteries (RFBs) are a promising technology for large-scale energy storage. Rapid research developments in RFB chemistries, materials and devices have laid critical foundations for cost-effective and long-lasting RFB systems. However, the lack of consistency in testing methods and assessment metrics makes it challenging to compare reported RFBs and evaluate their potential for practical applications. Here we discuss RFB assessment methods and performance metrics in direct relation to their working principles and degradation mechanisms. We first introduce basic cell attributes and performance metrics and describe common misconceptions in testing and performance comparison. We discuss major RFB decay mechanisms and highlight bottlenecks in organic, inorganic and solid-hybrid RFBs. Testing protocols, reporting practices and comparison criteria are proposed under a general framework of symmetric and asymmetric full RFBs. These recommendations can be broadly applied to a wide range of flow battery chemistries to facilitate future benchmarking and RFB development.

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Fig. 1: Fundamental illustrations of RFBs.
Fig. 2: Role of areal capacity and SOC in RFB testing and summary of reported RFBs.
Fig. 3: Recommended testing protocols and data analysis of three major RFB cell testing configurations.

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References

  1. Park, M., Ryu, J., Wang, W. & Cho, J. Material design and engineering of next-generation flow-battery technologies. Nat. Rev. Mater. 2, 16080 (2016).

    Article  Google Scholar 

  2. Li, L. et al. A stable vanadium redox-flow battery with high energy density for large-scale energy storage. Adv. Energy Mater. 1, 394–400 (2011).

    Article  Google Scholar 

  3. 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 

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

    Article  Google Scholar 

  5. Li, Z., Weng, G., Zou, Q., Cong, G. & Lu, Y.-C. A high-energy and low-cost polysulfide/iodide redox flow battery. Nano Energy 30, 283–292 (2016).

    Article  Google Scholar 

  6. Xie, C., Liu, Y., Lu, W., Zhang, H. & Li, X. Highly stable zinc-iodine single flow batteries with super high energy density for stationary energy storage. Energy Environ. Sci. 12, 1834–1839 (2019).

    Article  Google Scholar 

  7. Li, B. et al. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery. Nat. Commun. 6, 6303 (2015).

    Article  Google Scholar 

  8. Weng, G.-M., Li, Z., Cong, G., Zhou, Y. & Lu, Y.-C. Unlocking the capacity of iodide for high-energy-density zinc/polyiodide and lithium/polyiodide redox flow batteries. Energy Environ. Sci. 10, 735–741 (2017).

    Article  Google Scholar 

  9. Zhao, Y. et al. A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage. Chem. Soc. Rev. 44, 7968–7996 (2015).

    Article  Google Scholar 

  10. Xie, C. et al. A highly reversible neutral zinc/manganese battery for stationary energy storage. Energy Environ. Sci. 13, 135–143 (2020).

    Article  Google Scholar 

  11. Wang, Z., Tam, L.-Y. S. & Lu, Y.-C. Flexible solid flow electrodes for high-energy scalable energy storage. Joule 3, 1677–1688 (2019).

    Article  Google Scholar 

  12. 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 

  13. Xiao, J. et al. Understanding and applying Coulombic efficiency in lithium metal batteries. Nat. Energy 5, 561–568 (2020).

    Article  Google Scholar 

  14. Darling, R., Gallagher, K., Xie, W., Su, L. & Brushett, F. Transport property requirements for flow battery separators. J. Electrochem. Soc. 163, A5029–A5040 (2015).

    Article  Google Scholar 

  15. Chen, Q., Eisenach, L. & Aziz, M. J. Cycling analysis of a quinone-bromide redox flow battery. J. Electrochem. Soc. 163, A5057–A5063 (2016).

    Article  Google Scholar 

  16. Tong, L. et al. 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. 19, 31684–31691 (2017).

    Article  Google Scholar 

  17. Skyllas‐Kazacos, M., Kazacos, G., Poon, G. & Verseema, H. Recent advances with UNSW vanadium‐based redox flow batteries. Int. J. Energy Res. 34, 182–189 (2010).

    Article  Google Scholar 

  18. Perry, M. L., Saraidaridis, J. D. & Darling, R. M. Crossover mitigation strategies for redox-flow batteries. Curr. Opin. Electrochem. 21, 311–318 (2020).

    Article  Google Scholar 

  19. Waters, S. E., Robb, B. H. & Marshak, M. P. Effect of chelation on iron-chromium redox flow batteries. ACS Energy Lett. 5, 1758–1762 (2020).

    Article  Google Scholar 

  20. 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 

  21. Dong, Y.-R., Kaku, H., Hanafusa, K., Moriuchi, K. & Shigematsu, T. A novel titanium/manganese redox flow battery. ECS Trans. 69, 59–67 (2015).

    Article  Google Scholar 

  22. Yuan, Z. et al. Advanced porous membranes with ultra-high selectivity and stability for vanadium flow batteries. Energy Environ. Sci. 9, 441–447 (2016).

    Article  Google Scholar 

  23. Zhou, H., Zhang, H., Zhao, P. & Yi, B. A comparative study of carbon felt and activated carbon based electrodes for sodium polysulfide/bromine redox flow battery. Electrochim. Acta 51, 6304–6312 (2006).

    Article  Google Scholar 

  24. Ma, D. et al. Highly active nanostructured CoS2/CoS heterojunction electrocatalysts for aqueous polysulfide/iodide redox flow batteries. Nat. Commun. 10, 3367 (2019).

    Article  Google Scholar 

  25. 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 

  26. Zhang, C. et al. Phenothiazine-based organic catholyte for high-capacity and long-life aqueous redox flow batteries. Adv. Mater. 31, 1901052 (2019).

    Article  Google Scholar 

  27. Park, M. et al. A high voltage aqueous zinc–organic hybrid flow battery. Adv. Energy Mater. 9, 1900694 (2019).

    Article  Google Scholar 

  28. 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 

  29. Kwabi, D. G. et al. Alkaline quinone flow battery with long lifetime at pH 12. Joule 2, 1894–1906 (2018).

    Article  Google Scholar 

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

    Article  Google Scholar 

  31. 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 

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

    Article  Google Scholar 

  33. Hu, B., DeBruler, C., Rhodes, Z. & Liu, T. L. Long-cycling aqueous organic redox flow battery (AORFB) toward sustainable and safe energy storage. J. Am. Chem. Soc. 139, 1207–1214 (2017).

    Article  Google Scholar 

  34. Yang, B. et al. High-performance aqueous organic flow battery with quinone-based redox couples at both electrodes. J. Electrochem. Soc. 163, A1442–A1449 (2016).

    Article  Google Scholar 

  35. Goulet, M.-A. et al. Extending the lifetime of organic flow batteries via redox state management. J. Am. Chem. Soc. 141, 8014–8019 (2019).

    Article  Google Scholar 

  36. Tong, L. et al. Molecular engineering of an alkaline naphthoquinone flow battery. ACS Energy Lett. 4, 1880–1887 (2019).

    Article  Google Scholar 

  37. Xie, C., Duan, Y., Xu, W., Zhang, H. & Li, X. A low-cost neutral zinc-iron flow battery with high energy density for stationary energy storage. Angew. Chem. Int. Ed. 56, 14953–14957 (2017).

    Article  Google Scholar 

  38. Roe, S., Menictas, C. & Skyllas-Kazacos, M. A high energy density vanadium redox flow battery with 3 M vanadium electrolyte. J. Electrochem. Soc. 163, A5023–A5028 (2015).

    Article  Google Scholar 

  39. 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 

  40. Li, Z. & Lu, Y.-C. Material design of aqueous redox flow batteries: fundamental challenges and mitigation strategies. Adv. Mater. 32, 2002132 (2020).

    Article  Google Scholar 

  41. Lee, J.-H. et al. Dendrite-free Zn electrodeposition triggered by interatomic orbital hybridization of Zn and single vacancy carbon defects for aqueous Zn-based flow batteries. Energy Environ. Sci. 13, 2839–2848 (2020).

    Article  Google Scholar 

  42. Yin, Y. et al. Dendrite-free zinc deposition induced by tin-modified multifunctional 3D host for stable zinc-based flow battery. Adv. Mater. 32, 1906803 (2020).

    Article  Google Scholar 

  43. Darling, R. M. & Perry, M. L. Half-cell, steady-state flow-battery experiments. ECS Trans. 53, 31–38 (2013).

    Article  Google Scholar 

  44. Ke, X. et al. Rechargeable redox flow batteries: flow fields, stacks and design considerations. Chem. Soc. Rev. 47, 8721–8743 (2018).

    Article  Google Scholar 

  45. Zheng, Q., Xing, F., Li, X., Ning, G. & Zhang, H. Flow field design and optimization based on the mass transport polarization regulation in a flow-through type vanadium flow battery. J. Power Sources 324, 402–411 (2016).

    Article  Google Scholar 

  46. 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 

  47. Jin, S. et al. A water-miscible quinone flow battery with high volumetric capacity and energy density. ACS Energy Lett. 4, 1342–1348 (2019).

    Article  Google Scholar 

  48. Wang, C. et al. Molecular design of fused-ring phenazine derivatives for long-cycling alkaline redox flow batteries. ACS Energy Lett. 5, 411–417 (2020).

    Article  Google Scholar 

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

    Article  Google Scholar 

  50. Yuan, Z., Duan, Y., Liu, T., Zhang, H. & Li, X. Toward a low-cost alkaline zinc-iron flow battery with a polybenzimidazole custom membrane for stationary energy storage. iScience 3, 40–49 (2018).

    Article  Google Scholar 

Download references

Acknowledgements

The work described herein was supported by a grant from the Research Grant Council (RGC) of the Hong Kong Special Administrative Region, China (project number T23-601/17-R).

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Authors and Affiliations

  1. Electrochemical Energy and Interfaces Laboratory, Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China

    Yanxin Yao, Jiafeng Lei, Yang Shi, Fei Ai & Yi-Chun Lu

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Correspondence to Yi-Chun Lu.

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Peer review information Nature Energy thanks Travis Anderson, Mike Perry and Wei Wang for their contribution to the peer review of this work.

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Numerical data used to generate the graphs in Fig. 2c,d.

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Yao, Y., Lei, J., Shi, Y. et al. Assessment methods and performance metrics for redox flow batteries. Nat Energy 6, 582–588 (2021). https://doi.org/10.1038/s41560-020-00772-8

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