Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Designing fast oxide-ion conductors based on La2Mo2O9


The ability of solid oxides to conduct oxide ions has been known for more than a century, and fast oxide-ion conductors (or oxide electrolytes) are now being used for applications ranging from oxide fuel cells to oxygen pumping devices1,2. To be technologically viable, these oxide electrolytes must exhibit high oxide-ion mobility at low operating temperatures. Because of the size and interaction of oxygen ions with the cationic network, high mobility can only be achieved with classes of materials with suitable structural features. So far, high mobility has been observed in only a small number of structural families, such as fluorite3,4,5, perovskites6,7, intergrowth perovskite/Bi2O2 layers8,9 and pyrochlores10,11. Here we report a family of solid oxides based on the parent compound12 La2Mo2O9 (with a different crystal structure from all known oxide electrolytes) which exhibits fast oxide-ion conducting properties. Like other ionic conductors2,13, this material undergoes a structural transition around 580 °C resulting in an increase of conduction by almost two orders of magnitude. Its conductivity is about 6 × 10-2 S cm-1 at 800 °C, which is comparable to that of stabilized zirconia, the most widely used oxide electrolyte. The structural similarity of La2Mo2O9 with β-SnWO4 (ref. 14) suggests a structural model for the origin of the oxide-ion conduction. More generally, substitution of a cation that has a lone pair of electrons by a different cation that does not have a lone pair—and which has a higher oxidation state—could be used as an original way to design other oxide-ion conductors.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Phase transition at 580 °C in La2Mo2O9 (vertical grey line).
Figure 2: Thermal evolution of complex impedance curves measured on La2Mo2O9 at three temperatures.
Figure 3: Arrhenius plot of the conductivity of La2Mo2O9 compared to that of two typical stabilized zirconias.
Figure 4: Crystallographic arrangement of cations in the crystal structure of La2Mo2O9 and LnPO4.

Similar content being viewed by others


  1. Steele,B. C. H. in High Conductivity Solid Ionic Conductors, Recent Trends and Applications (ed. Takahashi, T.) 402–446 (World Scientific, Singapore, 1989).

    Book  Google Scholar 

  2. Boivin,J. C. & Mairesse,G. Recent material developments in fast oxide ion conductors. Chem. Mater. 10, 2870–2888 (1998).

    Article  CAS  Google Scholar 

  3. Subbarao,E. C. in Advances in Ceramics (eds Heuer, A. H. & Hobbs, L. W.) Vol. 3, Science and Technology of Zirconia I 1– 24 (American Ceramic Society, Columbus, Ohio, 1981).

    Google Scholar 

  4. Takahashi,T. & Iwara,H. High oxide ion conduction in sintered oxides of the system bismuth oxide-tungsten oxide. J. Appl. Electrochem. 3, 65–72 (1973 ).

    Article  Google Scholar 

  5. Harwig,H. A. & Gerards,A. G. Electrical properties of the α, β, γ and δ phases of bismuth sesquioxide. J. Solid State Chem. 26, 265–274 ( 1978).

    Article  ADS  CAS  Google Scholar 

  6. Ishihara,T., Matsuda,H. & Takita,Y. Doped LaGaO3 perovskite type oxide as a new oxide ionic conductor. J. Am. Chem. Soc. 116, 3801–3803 (1994).

    Article  CAS  Google Scholar 

  7. Feng,M. & Goodenough,J. B. A superior oxide-ion electrolyte. Eur. J. Solid State Inorg. Chem. 31, 663 –672 (1994).

    CAS  Google Scholar 

  8. Abraham,F., Debreuille-Gresse,M. F., Mairesse, G. & Nowogrocki,G. Phase transition and ionic conductivity in bismuth vanadate (Bi4V 2O11), an oxide with a layered structure. Solid State Ionics 28–30, 529–532 (1988).

    Article  Google Scholar 

  9. Abraham,F., Boivin,J. C., Mairesse,G. & Nowogrocki,G. The BIMEVOX series: a new family of high performances oxide ion conductors. Solid State Ionics 40–41, 934– 937 (1990).

    Article  Google Scholar 

  10. Tuller,H. L. Semiconduction and mixed ionic-electronic conduction in nonstoichiometric oxides: impact and control. Solid State Ionics 94, 63–74 (1997).

    Article  CAS  Google Scholar 

  11. Kramer,S. A. & Tuller,H. L. A novel titanate-based oxygen ion conductor: Gd2Ti2O7. Solid State Ionics 82, 15–23 ( 1995).

    Article  CAS  Google Scholar 

  12. Fournier,J. P., Fournier,J. & Kohlmuller, R. Etude des systèmes La2O3-MoO 3, Y2O3-MoO3 et des phases Ln 6MoO12. Bull. Soc. Chim. Fr. 4277–4283 (1970).

  13. Kendall,K. R., Navas,C., Thomas,J. K. & zur Loye,H. -C. Recent developments in perovskite-based ion conductors. Solid State Ionics 82, 215–223 (1995).

    Article  CAS  Google Scholar 

  14. Jeitschko,W. & Sleight,A. W. Synthesis, properties and crystal structure of β-SnWO4. Acta Crystallogr. B 28, 3174–3178 (1972).

    Article  CAS  Google Scholar 

  15. Lacorre,P. & Retoux,R. First direct synthesis by high energy ball milling of a new lanthanum molybdate. J. Solid State Chem. 132, 443–446 ( 1997).

    Article  ADS  CAS  Google Scholar 

  16. Kuang,W., Fan,Y., Qiu,J. & Chen,Y. Ultrafine La-Mo and Ce-Mo complex oxide particle catalysts for selective oxidation of toluene. J. Mater. Chem. 8, 19– 20 (1998).

    Article  CAS  Google Scholar 

  17. Goutenoire,F., Isnard,O., Retoux,R. & Lacorre,P. On the crystal structure of La2Mo2O9, a new fast oxide-ion conductor. Chem. Mater. (submitted).

  18. Wagner,J. B. & Wagner,C. Electrical conductivity measurements on cuprous halides. J. Chem. Phys. 26, 1597 –1601 (1957).

    Article  ADS  CAS  Google Scholar 

  19. Sheldrick,G. M. Phase annealing in SHELX-90: direct methods for larger structures. Acta Crystallogr. A 46, 467–473 (1990).

    Article  Google Scholar 

  20. Wells,A. F. Structural Inorganic Chemistry 5th edn, 1187 (Oxford Univ. Press, New York, 1987).

    Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Philippe Lacorre.

Supplementary information

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lacorre, P., Goutenoire, F., Bohnke, O. et al. Designing fast oxide-ion conductors based on La2Mo2O9. Nature 404, 856–858 (2000).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing