Ionic conductivity of sodium–strontium germanate Na4SrGe6O15

Resumo

The electrical conductivity of sodium–strontium germanate Na₄SrGe₆O₁₅ (sp. gr. P6₃/m) has been studied by impedance spectroscopy in the frequency range of 10²–4 × 10⁴ Hz and a temperature range of 450–600 K. Na4SrGe6O15 crystals were obtained by hydrothermal technique in the Na₂O–SrO–GeO₂–H₂O system (temperature t = 300–600°C and pressure p = 1.4 × 10⁸ Pа in the dissolution zone). The ionic conductivity of ceramic Na₄SrGe₆O₁₅ samples is σ = 2.2 × 10^–6 S/cm (at 573 K), the activation energy of Na⁺ ion transfer is E_a = 0.70 ± 0.03 eV.