Abstract

Polycrystalline Li₂BaP₂O₇ was obtained by heating a stoichiometric mixture of Li₂CO₃, BaCO₃ and NH₄H₂PO₄ at 750 °C for 12 hours in an air atmosphere. Co-doped samples Li_2 − 2xCo_xBaP₂O₇ (0.02 ≤ x ≤ 0.06) were prepared in the same way by adding predetermined amounts of cobalt(II) acetate tetrahydrate Co(CH₃COO)₂·4H₂O in the reaction mixture. The identity of the compounds was confirmed by elemental and X-ray diffraction analysis. The ionic conductivity, ascribed to the Li⁺ ion motion, was analysed by impedance measurements (frequency range: 1–10⁵ Hz, temperature range: 150–600 °C) on polycrystalline pellets sintered at 720 °C for 12 hours. The ionic conductivity is discussed on the basis of the structural characteristics of the samples.