The environmental benefits of fuel cells have been increasingly appreciated in recent years. Among candidate electrolytes for solid-oxide fuel cells, yttrium-doped barium zirconate has garnered attention because of its high proton conductivity, particularly in the intermediate-temperature region targeted for cost-effective solid-oxide fuel cell operation, and its excellent chemical stability. However, fundamental questions surrounding the defect chemistry and macroscopic proton transport mechanism of this material remain, especially in regard to the possible role of proton trapping. Here we show, through a combined thermogravimetric and a.c. impedance study, that macroscopic proton transport in yttrium-doped barium zirconate is limited by proton–dopant association (proton trapping). Protons must overcome the association energy, 29 kJ mol−1, as well as the general activation energy, 16 kJ mol−1, to achieve long-range transport. Proton nuclear magnetic resonance studies show the presence of two types of proton environment above room temperature, reflecting differences in proton–dopant configurations. This insight motivates efforts to identify suitable alternative dopants with reduced association energies as a route to higher conductivities.
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Kreuer, K. D. Proton-conducting oxides. Annu. Rev. Mater. Res. 33, 333–359 (2003).
Yamazaki, Y., Hernandez-Sanchez, R. & Haile, S. M. High total proton conductivity in large-grained yttrium-doped barium zirconate. Chem. Mater. 21, 2755–2762 (2009).
Fabbri, E., Pergolesi, D. & Traversa, E. Materials challenges toward proton-conducting oxide fuel cells: A critical review. Chem. Soc. Rev. 39, 4355–4369 (2010).
Kreuer, K. D. Aspects of the formation and mobility of protonic charge carriers and the stability of perovskite-type oxides. Solid State Ion. 125, 285–302 (1999).
Islam, M. S., Slater, P. R., Tolchard, J. R. & Dinges, T. Doping and defect association in AZrO3 (A = Ca, Ba) and LaMO3 (M = Sc, Ga) perovskite-type ionic conductors. Dalton Trans. 3061–3066 (2004).
Norby, T., Wideroe, M., Glockner, R. & Larring, Y. Hydrogen in oxides. Dalton Trans. 3012–3018 (2004).
Matzke, T. et al. Quasielastic thermal neutron scattering experiment on the proton conductor SrCe0.95Yb0.05H0.02O2.985 . Solid State Ion. 86-88, 621–628 (1996).
Stokes, S. J. & Islam, M. S. Defect chemistry and proton-dopant association in BaZrO3 and BaPrO3 . J. Mater. Chem. 20, 6258–6264 (2010).
Björketun, M. E., Sundell, P. G., Wahnström, G. & Engberg, D. A kinetic Monte Carlo study of proton diffusion in disordered perovskite structured lattices based on first-principles calculations. Solid State Ion. 176, 3035–3040 (2005).
Björketun, M. E., Sundell, P. G. & Wahnström, G. Effect of acceptor dopants on the proton mobility in BaZrO3: A density functional investigation. Phys. Rev. B 76, 054307 (2007).
Karlsson, M. et al. Using neutron spin-echo to investigate proton dynamics in proton-conducting perovskites. Chem. Mater. 22, 740–742 (2010).
Braun, A. et al. Proton diffusivity in the BaZr0.9Y0.1O3−δ proton conductor. J. Appl. Electrochem. 39, 471–475 (2009).
Karlsson, M. et al. Quasielastic neutron scattering of hydrated BaZr0.90A0.10O2.95 (A = Y and Sc). Solid State Ion. 180, 22–28 (2009).
Oriani, R. A. The diffusion and trapping of hydrogen in steel. Acta Metall. 18, 147–157 (1970).
Maier, J. Physical Chemistry of Ionic Materials 177–200 (Wiley, 2005).
Kreuer, K. D. et al. Proton conducting alkaline earth zirconates and titanates for high drain electrochemical applications. Solid State Ion. 145, 295–306 (2001).
Björketun, M. E., Sundell, P. G. & Wahnström, G. Structure and thermodynamic stability of hydrogen interstitials in BaZrO3 perovskite oxide from density functional calculations. Faraday Discuss. 134, 247–265 (2007).
Buannic, L., Blanc, F., Hung, I., Gan, Z. H. & Grey, C. P. Probing the local structures and protonic conduction pathways in scandium substituted BaZrO3 by multinuclear solid-state NMR spectroscopy. J. Mater. Chem. 20, 6322–6332 (2010).
Buannic, L. Solid State NMR Study of Protonic Conductors for Applications As Electrolyte Materials in Solid Oxide Fuel Cells PhD thesis (State Univ. New York, 2011).
Maekawa, H. et al. High temperature proton NMR study of yttrium doped barium cerates. Solid State Commun. 130, 73–77 (2004).
Steigel, A. & Spiess, H. W. Dynamic NMR Spectroscopy (Springer, 1978).
Holmes, L. et al. Variable-temperature O-17 NMR study of oxygen motion in the anionic conductor Bi26Mo10O69 . Chem. Mater. 20, 3638–3648 (2008).
Shewmon, P. Diffusion in Solids 2nd edn (TMS, 1989).
Yamazaki, Y., Babilo, P. & Haile, S. M. Defect chemistry of yttrium-doped barium zirconate: A thermodynamic analysis of water uptake. Chem. Mater. 20, 6352–6357 (2008).
Heo, P., Ito, K., Tomita, A. & Hibino, T. A proton-conducting fuel cell operating with hydrocarbon fuels. Angew. Chem. Int Ed. 47, 7841–7844 (2008).
Haryanto, A., Fernando, S., Murali, N. & Adhikari, S. Current status of hydrogen production techniques by steam reforming of ethanol: A review. Energy Fuels 19, 2098–2106 (2005).
Steele, B. C. H. & Heinzel, A. Materials for fuel-cell technologies. Nature 414, 345–352 (2001).
This work was supported by the Japan Science Technology Agency, PRESTO and the Gordon and Betty Moore Foundation. Y.O. thanks the JSPS Institutional Program for Young Researcher Overseas Visits. F.B., L.B. and C.P.G. acknowledge financial support from the NSF under grant DMR0804737; F.B. also thanks the EU Marie Curie actions for an International Incoming fellowship 2011–2013 (grant no. 275212) and Clare Hall, University of Cambridge, UK for a Research fellowship. We thank L. Sperrin and B. Y. Zhu for fruitful discussions.
The authors declare no competing financial interests.
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Yamazaki, Y., Blanc, F., Okuyama, Y. et al. Proton trapping in yttrium-doped barium zirconate. Nature Mater 12, 647–651 (2013). https://doi.org/10.1038/nmat3638
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