Correlation between microstructure and ionic conductivity in titanium-doped lithium tantalum phosphate (LiTa2PO8) ceramics

LiTa 2 PO 8 (LTPO) is considered as a promising candidate for application as a solid electrolyte in Li-ion technology, owing to its high grain conductivity, exceeding 1 mS/cm, and total ionic conductivity values that approach the bulk conductivity at room temperature. In this study, we investigate the effect of titanium doping on the structural, microstructural, and electrical characteristics of LTPO ceramics prepared at various sintering temperatures. While the introduction of Ti dopant into the LTPO crystal structure did not significantly alter the grain conductivity, which remained consistent at approximately 1–2 mS/cm, it induced notable changes in the microstructure and phase purity, influencing total electrical properties. However, the effect of Ti doping on total ionic conductivity was found to be less pronounced compared to the influence of the sintering process. Among the investigated samples, those sintered at 1200 °C exhibited the highest total ionic conductivity, reaching 0.49 mS/cm, highlighting the critical role of sintering temperature in optimizing the material's electrical performance.