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Ion-specific phenomena limit energy recovery in forward-biased bipolar membranes

Nature Chemical Engineering volume 2, pages 63–76 (2025)Cite this article

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Abstract

The ability for bipolar membranes (BPMs) to interconvert voltage and pH makes them attractive materials for use in energy conversion and storage. Reverse-biased BPMs, which use electrical voltage to dissociate water into acid and base, have become increasingly well studied. However, forward-biased BPMs (FB-BPMs), in which voltage is extracted from pH gradients through recombination, require further study. Here physics-based modeling elucidates how the complex coupling of transport and kinetics dictates the performance of FB-BPMs in electrochemical devices. Simulations reveal that the open-circuit potential of FB-BPMs is dictated by the balance of ion recombination and crossover, where recombination of buffering counter-ions attenuates the open-circuit potential. Counter-ion mass-transport limitations and uptake of ionic impurities limit achievable current densities by reducing the applied pH gradient or the available fixed-charge sites that mediate recombination. The model highlights the importance of selective ion management in mitigating energy losses and provides insight into the rational material design of FB-BPMs for energy applications.

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Fig. 1: Overview of FB-BPMs.
Fig. 2: Theory resolves attenuation of OCP in FB-BPMs.
Fig. 3: Modeling reveals the nature of limiting and overlimiting current density in FB-BPMs.
Fig. 4: Theory identifies losses in energy recovery for FB-BPMs with competitive counter-ions.
Fig. 5: CO2 absorption and co-ion crossover severely attenuates current and power density in FB-BPMs.
Fig. 6: Voltage loss and sensitivity analysis reveal dominant losses and opportunities for future engineered materials.

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All data associated with the figures in this Article can be found in Supplementary Data. Source data are provided with this paper.

References

  1. Pärnamäe, R. et al. Bipolar membranes: a review on principles, latest developments, and applications. J. Memb. Sci. 617, 118538 (2021).

    Google Scholar 

  2. Blommaert, M. A. et al. Insights and challenges for applying bipolar membranes in advanced electrochemical energy systems. ACS Energy Lett. 6, 2539–2548 (2021).

    CAS  PubMed  PubMed Central  Google Scholar 

  3. Bui, J. C. et al. Multi-scale physics of bipolar membranes in electrochemical processes. Nat. Chem. Eng. 1, 45–60 (2024).

    Google Scholar 

  4. Lucas, É. et al. Asymmetric bipolar membrane for high current density electrodialysis operation with exceptional stability. ACS Energy Lett. 9, 5596–5605 (2024).

    CAS  Google Scholar 

  5. Oener, S. Z., Foster, M. J. & Boettcher, S. W. Accelerating water dissociation in bipolar membranes and for electrocatalysis. Science 369, 1099–1103 (2020).

    CAS  PubMed  Google Scholar 

  6. Toh, W. L., Dinh, H. Q., Chu, A. T., Sauvé, E. R. & Surendranath, Y. The role of ionic blockades in controlling the efficiency of energy recovery in forward bias bipolar membranes. Nat. Energy 8, 1405–1416 (2023).

    CAS  Google Scholar 

  7. Dinh, H. Q., Toh, W. L., Chu, A. T. & Surendranath, Y. Neutralization short-circuiting with weak electrolytes erodes the efficiency of bipolar membranes. ACS Appl. Mater. Interfaces 15, 4001–4010 (2023).

    CAS  PubMed  Google Scholar 

  8. Gabrielsson, E. O., Tybrandt, K. & Berggren, M. Ion diode logics for pH control. Lab Chip 12, 2507–2513 (2012).

    CAS  PubMed  Google Scholar 

  9. Blommaert, M. A. et al. Orientation of a bipolar membrane determines the dominant ion and carbonic species transport in membrane electrode assemblies for CO2 reduction. J. Mater. Chem. A 9, 11179–11186 (2021).

    CAS  Google Scholar 

  10. Peng, S. et al. A self-humidifying acidic–alkaline bipolar membrane fuel cell. J. Power Sources 299, 273–279 (2015).

    CAS  Google Scholar 

  11. Mitchell, J. B., Chen, L., Langworthy, K., Fabrizio, K. & Boettcher, S. W. Catalytic proton–hydroxide recombination for forward-bias bipolar membranes. ACS Energy Lett. 7, 3967–3973 (2022).

    CAS  Google Scholar 

  12. Yan, Z. et al. High-voltage aqueous redox flow batteries enabled by catalyzed water dissociation and acid-base neutralization in bipolar membranes. ACS Cent. Sci. 7, 1028–1035 (2021).

    CAS  PubMed  PubMed Central  Google Scholar 

  13. Chen, R. Redox flow batteries: mitigating cross-contamination via bipolar redox-active materials and bipolar membranes. Curr. Opin. Electrochem. 37, 101188 (2023).

    CAS  Google Scholar 

  14. Xi, D. et al. Mild pH-decoupling aqueous flow battery with practical pH recovery. Nat. Energy 9, 479–490 (2024).

    CAS  Google Scholar 

  15. Bui, J. C., Digdaya, I., Xiang, C., Bell, A. T. & Weber, A. Z. Understanding multi-ion transport mechanisms in bipolar membranes. ACS Appl. Mater. Interfaces 12, 52509–52526 (2020).

    CAS  PubMed  Google Scholar 

  16. Newman, J. & Thomas-Alyea, K. E. Electrochemical Systems (John Wiley and Sons, 2004).

  17. Pärnamäe, R. et al. Origin of limiting and overlimiting currents in bipolar membranes. Environ. Sci. Technol. 57, 9664–9674 (2023).

    PubMed  PubMed Central  Google Scholar 

  18. Crandall, B. S., Overa, S., Shin, H. & Jiao, F. Turning carbon dioxide into sustainable food and chemicals: how electrosynthesized acetate is paving the way for fermentation innovation. Acc. Chem. Res. 56, 1505–1516 (2023).

    CAS  PubMed  Google Scholar 

  19. Ramdin, M. et al. High pressure electrochemical reduction of CO2 to formic acid/formate: a comparison between bipolar membranes and cation exchange membranes. Ind. Eng. Chem. Res. 58, 1834–1847 (2019).

    CAS  PubMed  PubMed Central  Google Scholar 

  20. Rabinowitz, J. A. & Kanan, M. W. The future of low-temperature carbon dioxide electrolysis depends on solving one basic problem. Nat. Commun. 11, 5231 (2020).

    CAS  PubMed  PubMed Central  Google Scholar 

  21. Peng, J., Roy, A. L., Greenbaum, S. G. & Zawodzinski, T. A. Effect of CO2 absorption on ion and water mobility in an anion exchange membrane. J. Power Sources 380, 64–75 (2018).

    CAS  Google Scholar 

  22. Yan, Z., Hitt, J. L., Zeng, Z., Hickner, M. A. & Mallouk, T. E. Improving the efficiency of CO2 electrolysis by using a bipolar membrane with a weak-acid cation exchange layer. Nat. Chem. 13, 33–40 (2021).

    CAS  PubMed  Google Scholar 

  23. Bui, J. C. et al. Analysis of bipolar membranes for electrochemical CO2 capture from air and oceanwater. Energy Environ. Sci. 16, 5076–5095 (2023).

    CAS  Google Scholar 

  24. She, X. et al. Pure-water-fed, electrocatalytic CO2 reduction to ethylene beyond 1,000 h stability at 10 A. Nat. Energy 9, 81–91 (2024).

    CAS  Google Scholar 

  25. Fischer, R., Dessiex, M. A., Marone, F. & Buchi, F. N. Gas-induced structural damages in forward-bias bipolar membrane CO2 electrolysis studied by fast X‑ray tomography. ACS Appl. Energy Mater. 7, 3590–3601 (2024).

  26. Bard, A. J. & Faulkner, L. R. Electrochemical Methods: Fundamentals and Applications (Wiley, 2001).

  27. Corpus, K. R. M. et al. Coupling covariance matrix adaptation with continuum modeling for determination of kinetic parameters associated with electrochemical CO2 reduction. Joule 7, 1289–1307 (2023).

    CAS  Google Scholar 

  28. Hansen, N. The CMA evolution strategy: a tutorial. Preprint at https://arxiv.org/abs/1604.00772 (2023).

  29. Pärnamäe, R. et al. The acid–base flow battery: sustainable energy storage via reversible water dissociation with bipolar membranes. Membranes 10, 1–20 (2020).

    Google Scholar 

  30. Yan, H. et al. Bipolar membrane-assisted reverse electrodialysis for high power density energy conversion via acid–base neutralization. J. Memb. Sci. 647, 120288 (2022).

    CAS  Google Scholar 

  31. Kitto, D. & Kamcev, J. The need for ion-exchange membranes with high charge densities. J. Memb. Sci. 677, 121608 (2023).

    CAS  Google Scholar 

  32. Kusoglu, A. & Weber, A. Z. New insights into perfluorinated sulfonic-acid ionomers. Chem. Rev. 117, 987–1104 (2017).

    CAS  PubMed  Google Scholar 

  33. Lees, E. W., Bui, J. C., Song, D., Weber, A. Z. & Berlinguette, C. P. Continuum model to define the chemistry and mass transfer in a bicarbonate electrolyzer. ACS Energy Lett. 7, 834–842 (2022).

    CAS  Google Scholar 

  34. Jouny, M., Luc, W. & Jiao, F. High-rate electroreduction of carbon monoxide to multi-carbon products. Nat. Catal. 1, 748–755 (2018).

    CAS  Google Scholar 

  35. Li, T., Lees, E. W., Zhang, Z. & Berlinguette, C. P. Conversion of bicarbonate to formate in an electrochemical flow reactor. ACS Energy Lett. 5, 2624–2630 (2020).

    CAS  Google Scholar 

  36. van Linden, N., Bandinu, G. L., Vermaas, D. A., Spanjers, H. & van Lier, J. B. Bipolar membrane electrodialysis for energetically competitive ammonium removal and dissolved ammonia production. J. Clean. Prod. 259, 120788 (2020).

    Google Scholar 

  37. Wheaton, R. M. & Bauman, W. C. Properties of strongly basic anion exchange resins. Ind. Eng. Chem. 43, 1088–1093 (1951).

    CAS  Google Scholar 

  38. Crothers, A. R., Darling, R. M., Kushner, D. I., Perry, M. L. & Weber, A. Z. Theory of multicomponent phenomena in cation-exchange membranes: part III. Transport in vanadium redox-flow-battery separators. J. Electrochem. Soc. 167, 013549 (2020).

  39. Andersen, M. B. et al. Current-induced membrane discharge. Phys. Rev. Lett. 109, 1–5 (2012).

    Google Scholar 

  40. Singh, S., Taketsugu, T. & Singh, R. K. Hydration, prediction of the pKa, and infrared spectroscopic study of sulfonated polybenzophenone (SPK) block-copolymer hydrocarbon membranes and comparisons with Nafion. ACS Omega 6, 32739–32748 (2021).

    CAS  PubMed  PubMed Central  Google Scholar 

  41. De Paul Nzuwah Nziko, V., Shih, J. L., Jansone-Popova, S. & Bryantsev, V. S. Quantum chemical prediction of pKa values of cationic ion-exchange groups in polymer electrolyte membranes. J. Phys. Chem. C 122, 2490–2501 (2018).

    Google Scholar 

  42. Krewer, U., Weinzierl, C., Ziv, N. & Dekel, D. R. Impact of carbonation processes in anion exchange membrane fuel cells. Electrochim. Acta 263, 433–446 (2018).

    CAS  Google Scholar 

  43. Keith, D. W., Holmes, G., St. Angelo, D. & Heidel, K. A process for capturing CO2 from the atmosphere. Joule 2, 1573–1594 (2018).

    CAS  Google Scholar 

  44. Suzuki, S., Muroyama, H., Matsui, T. & Eguchi, K. Influence of CO2 dissolution into anion exchange membrane on fuel cell performance. Electrochim. Acta 88, 552–558 (2013).

    CAS  Google Scholar 

  45. Bui, J. C. et al. Engineering catalyst—electrolyte microenvironments to optimize the activity and selectivity for the electrochemical reduction of CO2 on Cu and Ag. Acc. Chem. Res. 55, 484–494 (2022).

    CAS  PubMed  Google Scholar 

  46. Tricker, A. W. et al. Engineering bipolar interfaces for water electrolysis using earth-abundant anodes. ACS Energy Lett. 8, 5275–5280 (2023).

    CAS  PubMed  PubMed Central  Google Scholar 

  47. Heßelmann, M. et al. Pure-water-fed forward-bias bipolar membrane CO2 electrolyzer. ACS Appl. Mater. Interfaces https://doi.org/10.1021/acsami.4c02799 (2024).

  48. Kushner, D. I., Crothers, A. R., Kusoglu, A. & Weber, A. Z. Transport phenomena in flow battery ion-conducting membranes. Curr. Opin. Electrochem. 21, 132–139 (2020).

    CAS  Google Scholar 

  49. Lucas, É., Han, L., Sullivan, I., Atwater, H. A. & Xiang, C. Measurement of ion transport properties in ion exchange membranes for photoelectrochemical water splitting. Front. Energy Res. 10, 1–11 (2022).

    Google Scholar 

  50. Craig, N. P. Electrochemical Behavior of Bipolar Membranes: PhD thesis, Univ. of California, Berkeley (2013).

  51. Onsager, L. & Fuoss, R. M. Irreversible processes in electrolytes. Diffusion, conductance, and viscous flow in arbitrary mixtures of strong electrolytes. J. Phys. Chem. 36, 2689–2778 (1932).

    CAS  Google Scholar 

  52. Onsager, L. Deviations from Ohm’s law in weak electrolytes. J. Chem. Phys. 2, 599–615 (1934).

    CAS  Google Scholar 

  53. Kaiser, V., Bramwell, S. T., Holdsworth, P. C. W. & Moessner, R. Onsager’s Wien effect on a lattice. Nat. Mater. 12, 1033–1037 (2013).

    CAS  PubMed  Google Scholar 

  54. Bui, J. C., Corpus, K. R. M., Bell, A. T. & Weber, A. Z. On the nature of field enhanced water dissociation in bipolar membranes. J. Phys. Chem. C 125, 24974–24987 (2021).

    CAS  Google Scholar 

  55. Lin, M., Digdaya, I. A. & Xiang, C. Modeling the electrochemical behavior and interfacial junction profiles of bipolar membranes at solar flux relevant operating current densities. Sustain. Energy Fuels 5, 2149–2158 (2021).

    CAS  Google Scholar 

  56. Kamcev, J. et al. Partitioning of mobile ions between ion exchange polymers and aqueous salt solutions: Importance of counter-ion condensation. Phys. Chem. Chem. Phys. 18, 6021–6031 (2016).

    CAS  PubMed  Google Scholar 

  57. Manning, G. S. Limiting laws and counterion condensation in polyelectrolyte solutions. 8. mixtures of counterions, species selectivity, and valence selectivity. J. Phys. Chem. 88, 6654–6661 (1984).

    CAS  Google Scholar 

  58. Purpura, G. et al. Modelling of selective ion partitioning between ion-exchange membranes and highly concentrated multi-ionic brines. J. Memb. Sci. 700, 122659 (2024).

    CAS  Google Scholar 

  59. Ramírez, P., Rapp, H. J., Reichle, S., Strathmann, H. & Mafé, S. Current–voltage curves of bipolar membranes. J. Appl. Phys. 72, 259–264 (1992).

    Google Scholar 

  60. Rodellar, C. G., Gisbert-Gonzalez, J. M., Sarabia, F., Roldan Cuenya, B. & Oener, S. Z. Ion solvation kinetics in bipolar membranes and at electrolyte-metal interfaces. Nat. Energy 9, 548–558 (2024).

    CAS  Google Scholar 

  61. Grew, K. N. & Chiu, W. K. S. A dusty fluid model for predicting hydroxyl anion conductivity in alkaline anion exchange membranes. J. Electrochem. Soc. 157, B327 (2010).

    CAS  Google Scholar 

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Acknowledgements

This material is based upon work supported by the US Department of Energy, Office of Science Energy Earthshot Initiative as part of the Center for Ionomer-based Water Electrolysis at Lawrence Berkeley National Laboratory under contract #DE-AC02-05CH11231. J.C.B. was supported in part by a fellowship award under contract FA9550-21-F-0003 through the National Defense Science and Engineering Graduate (NDSEG) Fellowship Program, sponsored by the Army Research Office (ARO). E.W.L acknowledges funding from the National Science and Engineering Research Council of Canada (NSERC). F.J.U.G. and T.N.S. acknowledge funding from the US Department of Energy, Office of Science Energy Earthshot Initiative as part of the Bipolar Membrane Science Foundations for the Energy Earthshot under contact #DE-SC0024713. T.N.S. acknowledges support from the National Science Foundation Graduate Research Fellowship (NSFGRFP) under grant no. DGE 2146752.

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Authors and Affiliations

  1. Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, CA, USA

    Justin C. Bui, Andrew K. Liu, Francisco Javier U. Galang & Alexis T. Bell

  2. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

    Justin C. Bui, Andrew K. Liu, Francisco Javier U. Galang, Alexis T. Bell & Adam Z. Weber

  3. Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

    Eric W. Lees, T. Nathan Stovall, Priyamvada Goyal & Adam Z. Weber

  4. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA

    Wei Lun Toh & Yogesh Surendranath

  5. Department of Chemistry, University of California Berkeley, Berkeley, CA, USA

    T. Nathan Stovall

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Contributions

J.C.B. conceived of the study, developed the continuum model and theory, and collected and analyzed simulation data. A.K.L. performed initial model calculations and validations. E.W.L., P.G. and F.J.U.G. assisted with theory development and provided modeling support. W.L.T. and T.N.S provided experimental data and assisted with data interpretation. J.C.B and E.W.L. prepared the initial draft of the manuscript. A.Z.W., A.T.B. and Y.S. supervised the project and assisted with data analysis and interpretation. All authors engaged in the writing and revision of the manuscript.

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Correspondence to Justin C. Bui or Adam Z. Weber.

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Nature Chemical Engineering thanks Sebastian Oener and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Extended data

Extended Data Table 1 List of fit parameters employed in model
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Supplementary information

Supplementary Information

Supplementary Figs. 1-75, Tables 1–6, discussion and methods.

Source data

Source Data Fig. 2

Electrochemical simulation data for FB-BPM open circuit potential, experimental data for comparison.

Source Data Fig. 3

Electrochemical simulation data for FB-BPM limiting current density.

Source Data Fig. 4

Electrochemical simulation data for FB-BPM in mixed electrolytes, experimental data for comparison.

Source Data Fig. 5

Electrochemical simulation data of FB-BPMs with absorbed CO2.

Source Data Fig. 6

Sensitivity analysis data of FB-BPM performance.

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Bui, J.C., Lees, E.W., Liu, A.K. et al. Ion-specific phenomena limit energy recovery in forward-biased bipolar membranes. Nat Chem Eng 2, 63–76 (2025). https://doi.org/10.1038/s44286-024-00154-x

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