Lithium-ionic conductivity of LixLa(1−x)/3NbO3 single crystals grown by the TSFZ method

Abstract

LixLa(1−x)/3NbO3 single crystals with various Li compositions (x = 0.05–0.15) were grown via the travelling solvent floating zone (TSFZ) method. The electron probe microanalysis (EPMA) and inductively couple plasma (ICP) analyses revealed that there is Li evaporation from the molten zone during crystal growth due to high temperature treatment. However, the Li concentration in the grown crystals increased as the nominal composition in the feeds increased. Additionally, the grown crystal of LixLa(1−x)/3NbO3 (x = 0.05–0.15) showed uniform composition measured by EPMA X-ray intensity distribution except when x = 0.15. The experimental result confirmed that the ionic conductivity of LixLa(1−x)/3NbO3 (x = 0.05–0.15) showed a maximum of σ = 1.2 × 10−4 S cm−1 with x = 0.07 composition in the grown crystal. The anisotropy of ionic conductivity was measured along the [100] and [001] directions of the solid electrolyte of the LixLa(1−x)/3NbO3 (x = 0.05–0.15) single crystal. The maximum anisotropic ionic conductivity of the crystals annealed in oxygen was σ[100]/σ[001] ≈ 1.6.