Preparation and properties of LixLa0.5TiO3 perovskite oxide electrolytes

Solid electrolytes with high lithium ionic conductivity and outstanding mechanical stability are essential for all solid‐state lithium ion batteries. Perovskite Li_xLa_0.5TiO₃ is one of the most promising as solid electrolytes candidates. Li_xLa_0.5TiO₃ with various initial Li₂O (0.5≤x≤0.569) is synthesized by traditional solid‐state reaction at high temperatures. The crystal structure is not remarkably affected by the Li₂O quantity, yet higher porosity is obtained as a result of excess Li₂O. The Young's modulus, hardness, and fracture toughness are evaluated with indentation method. The Young's modulus increases from 72 to 148 GPa with increasing Li₂O, which means that a small variation of Li quantity in Li_xLa_0.5TiO₃ results in over a 100% change in Young's modulus. However, the fracture toughness exhibits an opposite trend with that of the Young's modulus. The high Young's modulus and fracture toughness could guarantee the structural integrity during cycle operations.