It was recalled that BaCeO3 possessed a high proton conductivity, but had a rather poor chemical stability in CO2-containing atmospheres, while BaZrO3 was quite stable but had a low proton conductivity. The properties of solid solutions between these compounds were therefore investigated. Compounds of the general form, BaCe0.9-xZrxM0.1O3, where M was Gd or Nd and x ranged from 0 to 0.4, were prepared via solid-state reaction and were characterized by using X-ray powder diffraction, thermal gravimetric analysis in flowing CO2, differential thermal analysis in flowing CO2, and alternating-current impedance spectroscopy in dry or H2-saturated Ar. The introduction of Zr into doped BaCeO3 greatly enhanced the chemical stability. In the case of the Nd-doped system, compositions with x = 0.2 or more did not react with CO2 under the present non-equilibrium conditions. In the case of the Gd-doped system, a composition with x = 0.4 did not react. The introduction of Zr also led to a decrease in conductivity.

Chemical Stability and Proton Conductivity of Doped BaCeO3-BaZrO3 Solid Solutions. K.H.Ryu, S.M.Haile: Solid State Ionics, 1999, 125[1-4], 355-67