Mixed proton and electron conducting double perovskite anodes for stable and efficient tubular proton ceramic electrolysers


Hydrogen production from water electrolysis is a key enabling energy storage technology for the large-scale deployment of intermittent renewable energy sources. Proton ceramic electrolysers (PCEs) can produce dry pressurized hydrogen directly from steam, avoiding major parts of cost-driving downstream separation and compression. However, the development of PCEs has suffered from limited electrical efficiency due to electronic leakage and poor electrode kinetics. Here, we present the first fully operational BaZrO3-based tubular PCE, with 10 cm2 active area and a hydrogen production rate above 15 Nml min−1. The novel steam anode Ba1−xGd0.8La0.2+xCo2O6−δ exhibits mixed p-type electronic and protonic conduction and low activation energy for water splitting, enabling total polarization resistances below 1 Ω cm2 at 600 °C and Faradaic efficiencies close to 100% at high steam pressures. These tubular PCEs are mechanically robust, tolerate high pressures, allow improved process integration and offer scale-up modularity.

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Fig. 1: Schematics of water electrolysis technologies and PCE membrane and transport.
Fig. 2: Phase segregation and microscopy of BGLC.
Fig. 3: PCE electrochemical performance and literature comparison.
Fig. 4: PCE cell performance and characterization.
Fig. 5: Technological viability of tubular PCEs.
Fig. 6: Charge transfer and CFD models of PCE system.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.


  1. 1.

    Hauch, A., Ebbesen, S. D., Jensen, S. H. & Mogensen, M. Highly efficient high temperature electrolysis. J. Mater. Chem. 18, 2331–2340 (2008).

    CAS  Article  Google Scholar 

  2. 2.

    Laguna-Bercero, M. Recent advances in high temperature electrolysis using solid oxide fuel cells: a review. J. Power Sources 203, 4–16 (2012).

    CAS  Article  Google Scholar 

  3. 3.

    Ebbesen, S. D., Jensen, S. H., Hauch, A. & Mogensen, M. B. High temperature electrolysis in alkaline cells, solid proton conducting cells and solid oxide cells. Chem. Rev. 114, 10697–10734 (2014).

    CAS  Article  Google Scholar 

  4. 4.

    Knibbe, R., Traulsen, M. L., Hauch, A., Ebbesen, S. D. & Mogensen, M. Solid oxide electrolysis cells: degradation at high current densities. J. Electrochem. Soc. 157, B1209–B1217 (2010).

    CAS  Article  Google Scholar 

  5. 5.

    Hauch, A., Jensen, S. H., Ramousse, S. & Mogensen, M. Performance and durability of solid oxide electrolysis cells. J. Electrochem. Soc. 153, A1741–A1747 (2006).

    CAS  Article  Google Scholar 

  6. 6.

    Wachsman, E. D. & Lee, K. T. Lowering the temperature of solid oxide fuel cells. Science 334, 935–939 (2011).

    CAS  Article  Google Scholar 

  7. 7.

    Ishihara, T., Jirathiwathanakul, N. & Zhong, H. Intermediate temperature solid oxide electrolysis cell using LaGaO3 based perovskite electrolyte. Energy Environ. Sci. 3, 665–672 (2010).

    CAS  Article  Google Scholar 

  8. 8.

    Iwahara, H., Uchida, H. & Maeda, N. High temperature fuel and steam electrolysis cells using proton conductive solid electrolytes. J. Power Sources 7, 293–301 (1982).

    CAS  Article  Google Scholar 

  9. 9.

    Norby, T. in Perovskite Oxide for Solid Oxide Fuel Cells (ed. Ishihara, T.) 217–241 (Springer, 2009).

  10. 10.

    Tong, J., Clark, D., Bernau, L., Sanders, M. & O’Hayre, R. Solid-state reactive sintering mechanism for large-grained yttrium-doped barium zirconate proton conducting ceramics. J. Mater. Chem. 20, 6333–6341 (2010).

    CAS  Article  Google Scholar 

  11. 11.

    Iwahara, H., Yajima, T., Hibino, T., Ozaki, K. & Suzuki, H. Protonic conduction in calcium, strontium and barium zirconates. Solid State Ion. 61, 65–69 (1993).

    CAS  Article  Google Scholar 

  12. 12.

    Duan, C. et al. Readily processed protonic ceramic fuel cells with high performance at low temperatures. Science 349, 1321–1326 (2015).

    CAS  Article  Google Scholar 

  13. 13.

    Choi, S. et al. Exceptional power density and stability at intermediate temperatures in protonic ceramic fuel cells. Nat. Energy 3, 202–210 (2018).

    CAS  Article  Google Scholar 

  14. 14.

    An, H. et al. A 5 × 5 cm2 protonic ceramic fuel cell with a power density of 1.3 W cm–2 at 600 °C. Nat. Energy 3, 870–875 (2018).

    CAS  Article  Google Scholar 

  15. 15.

    Duan, C. et al. Highly efficient reversible protonic ceramic electrochemical cells for power generation and fuel production. Nat. Energy 4, 230–240 (2019).

    CAS  Article  Google Scholar 

  16. 16.

    Morejudo, S. et al. Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor. Science 353, 563–566 (2016).

    CAS  Article  Google Scholar 

  17. 17.

    Malerød-Fjeld, H. et al. Thermo-electrochemical production of compressed hydrogen from methane with near-zero energy loss. Nat. Energy 2, 923–931 (2017).

    Article  Google Scholar 

  18. 18.

    Babiniec, S. M., Ricote, S. & Sullivan, N. P. Characterization of ionic transport through BaCe0.2Zr0.7Y0.1O3−δ membranes in galvanic and electrolytic operation. Int. J. Hydrogen Energy 40, 9278–9286 (2015).

    CAS  Article  Google Scholar 

  19. 19.

    Bi, L., Shafi, S. P. & Traversa, E. Y-doped BaZrO3 as a chemically stable electrolyte for proton-conducting solid oxide electrolysis cells (SOECs). J. Mater. Chem. A 3, 5815–5819 (2015).

    CAS  Article  Google Scholar 

  20. 20.

    Li, S. & Xie, K. Composite oxygen electrode based on LSCF and BSCF for steam electrolysis in a proton-conducting solid oxide electrolyzer. J. Electrochem. Soc. 160, F224–F233 (2013).

    CAS  Article  Google Scholar 

  21. 21.

    Matsumoto, H., Sakai, T. & Okuyama, Y. Proton-conducting oxide and applications to hydrogen energy devices. Pure Appl. Chem. 85, 427–435 (2012).

    Article  Google Scholar 

  22. 22.

    Gan, Y. et al. Composite oxygen electrode based on LSCM for steam electrolysis in a proton conducting solid oxide electrolyzer. J. Electrochem. Soc. 159, F763–F767 (2012).

    CAS  Article  Google Scholar 

  23. 23.

    Shang, M., Tong, J. & O’Hayre, R. A promising cathode for intermediate temperature protonic ceramic fuel cells: BaCo0.4Fe0.4Zr0.2O3−δ. RSC Adv. 3, 15769–15775 (2013).

    CAS  Article  Google Scholar 

  24. 24.

    Strandbakke, R. et al. Gd- and Pr-based double perovskite cobaltites as oxygen electrodes for proton ceramic fuel cells and electrolyser cells. Solid State Ion. 278, 120–132 (2015).

    CAS  Article  Google Scholar 

  25. 25.

    Poetzsch, D., Merkle, R. & Maier, J. Proton conductivity in mixed-conducting BSFZ perovskite from thermogravimetric relaxation. Phys. Chem. Chem. Phys. 16, 16446–16453 (2014).

    CAS  Article  Google Scholar 

  26. 26.

    Zohourian, R., Merkle, R. & Maier, J. Proton uptake into the protonic cathode material BaCo0.4Fe0.4Zr0.2O3−δ and comparison to protonic electrolyte materials. Solid State Ion. 299, 64–69 (2017).

    CAS  Article  Google Scholar 

  27. 27.

    Strandbakke, R., Vøllestad, E., Robinson, S. A., Fontaine, M.-L. & Norby, T. Ba0.5Gd0.8La0.7Co2O6−δ infiltrated in porous BaZr0.7Ce0.2Y0.1O3 backbones as electrode material for proton ceramic electrolytes. J. Electrochem. Soc. 164, F196–F202 (2017).

    CAS  Article  Google Scholar 

  28. 28.

    Vollestad, E., Schrade, M., Segalini, J., Strandbakke, R. & Norby, T. Relating defect chemistry and electronic transport in the double perovsksite Ba1−xGd0.8La0.2+xCo2O6−δ(BGLC). J. Mater. Chem. A 5, 15743–15751 (2017).

    Article  Google Scholar 

  29. 29.

    Brieuc, F., Dezanneau, G., Hayoun, M. & Dammak, H. Proton diffusion mechanisms in the double perovskite cathode material GdBaCo2O5.5: a molecular dynamics study. Solid State Ion. 309, 187–191 (2017).

    CAS  Article  Google Scholar 

  30. 30.

    Mokkelbost, T. et al. High-temperature proton-conducting lanthanum ortho-niobate-based materials. Part II: sintering properties and solubility of alkaline earth oxides. J. Am. Ceram. Soc. 91, 879–886 (2008).

    CAS  Article  Google Scholar 

  31. 31.

    Tong, J., Clark, D., Hoban, M. & O’Hayre, R. Cost-effective solid-state reactive sintering method for high conductivity proton conducting yttrium-doped barium zirconium ceramics. Solid State Ion. 181, 496–503 (2010).

    CAS  Article  Google Scholar 

  32. 32.

    Kwon, O. H. & Choi, G. M. Electrical conductivity of thick film YSZ. Solid State Ion. 177, 3057–3062 (2006).

    CAS  Article  Google Scholar 

  33. 33.

    Timakul, P., Jinawath, S. & Aungkavattana, P. Fabrication of electrolyte materials for solid oxide fuel cells by tape-casting. Ceram. Int. 34, 867–871 (2008).

    CAS  Article  Google Scholar 

  34. 34.

    Kim, S. J., Kim, K. J., Dayaghi, A. M. & Choi, G. M. Polarization and stability of La2NiO4+δ in comparison with La0.6Sr0.4Co0.2Fe0.8O3−δ as air electrode of solid oxide electrolysis cell. Int. J. Hydrogen Energy 41, 14498–14506 (2016).

    CAS  Article  Google Scholar 

  35. 35.

    Jacobsen, T., Chatzichristodoulou, C. & Mogensen, M. B. Fermi potential across working solid oxide cells with zirconia or ceria electrolytes. ECS Trans. 61, 203–214 (2014).

    CAS  Article  Google Scholar 

  36. 36.

    Zhu, H. & Kee, R. J. Membrane polarization in mixed-conducting ceramic fuel cells and electrolyzers. Int. J. Hydrogen Energy 41, 2931–2943 (2016).

    CAS  Article  Google Scholar 

  37. 37.

    Kreuer, K. D. Proton-conducting oxides. Annu. Rev. Mater. Res. 33, 333–359 (2003).

    CAS  Article  Google Scholar 

  38. 38.

    Nikodemski, S., Tong, J. & O’Hayre, R. Solid-state reactive sintering mechanism for proton conducting ceramics. Solid State Ion. 253, 201–210 (2013).

    CAS  Article  Google Scholar 

  39. 39.

    Ricote, S., Manerbino, A., Sullivan, N. P. & Coors, W. G. Preparation of dense mixed electron- and proton-conducting ceramic composite materials using solid-state reactive sintering: BaCe0.8Y0.1M0.1O3−δ–Ce0.8Y0.1M0.1O2−δ (M = Y, Yb, Er, Eu). J. Mater. Sci. 49, 4332–4340 (2014).

    CAS  Article  Google Scholar 

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The work leading to these results has received funding from the Research Council of Norway (grant 236828) and from the European Union’s Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement 621244 (‘ELECTRA’) and Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement 779486 (‘GAMER’). This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe research.

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E.V., R.S., M.-L.F., J.M.S. and T.N. conceived, designed and supervised the research. D.B. prepared the tubular half cells. M.-L.F. prepared electrodes. E.V. and R.S. developed and synthesized electrode materials, fabricated the electrolysers from tubular half cells and electrode materials and conducted electrochemical characterization. E.V. made the electrochemical model. M.T. conducted stability tests and humidity measurements. D.R.C. performed the TEM work and graphical processing. D.C. and J.M.S. carried out the CFD calculations. All authors contributed to writing the manuscript.

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Correspondence to Truls Norby.

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Supplementary Notes, Supplementary Figs. 1–15, Supplementary Tables 1–4, Supplementary references 1–14

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Vøllestad, E., Strandbakke, R., Tarach, M. et al. Mixed proton and electron conducting double perovskite anodes for stable and efficient tubular proton ceramic electrolysers. Nat. Mater. 18, 752–759 (2019). https://doi.org/10.1038/s41563-019-0388-2

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