High temperature protonic conduction in Sr-doped LaP3O9

Koji Amezawa, Yoshiharu Uchimoto, Yoichi Tomii

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26 Citations (Scopus)


Electrical conduction of Sr-doped LaP3O9 ([Sr]/{[La] + [Sr]} = 2-10 mol%) was investigated under 0.4-5 kPa of p(H2O) and 0.01-100 kPa of p(O2) or 0.3-3 kPa of p(H2) at 573-973 K. Sr-doped LaP3O9 showed apparent H/D isotope effect on conductivity regardless of the Sr-doping level under both H2O/O2 oxidizing and H2/H2O reducing conditions at investigated temperatures. Conductivities of the material were almost independent of p(O2) and p(H2O). These results demonstrated that the Sr-doped LaP3O9 exhibited protonic conduction under wide ranges of p(O2), p(H2O) and temperature. The conductivity of the Sr-doped LaP3O9 increased with increasing Sr concentration up to its solubility limit, ca. 3 mol%, while the further Sr-doping slightly degraded the conductivity. These indicate that Sr2+ substitution for La3+ leads to proton dissolution into the material and induced protonic conduction. Conductivities of the 3 mol% Sr-doped sample were 2 × 10- 6-5 × 10- 4 S cm- 1 at 573-973 K.

Original languageEnglish
Pages (from-to)2407-2411
Number of pages5
JournalSolid State Ionics
Issue number26-32 SPEC. ISS.
Publication statusPublished - 2006 Oct 31


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