Study on the Preparation of High Intrinsic Conductivity Perovskite Li_0.33La_0.56TiO₃ Solid-State Electrolyte by Systematic Process Optimization

Li_0.33La_0.56TiO₃ (LLTO) perovskite-type solid-state electrolyte is one of the solid-state electrolytes, which is expected to achieve industrial production. However, research focused on a single factor and the simplification of the preparation process constrained the bulk conductivity of LLTO. This study systematically investigated the influence of process parameters on the intrinsic conductivity of perovskite-type solid-state electrolytes, focusing on pre-sintering temperature, lithium compensation, and sintering temperature, which are important processes for LLTO. The experimental results show that the optimization of process parameters can promote grain growth to a certain extent, increase the uniformity of grain size, and promote the densification of materials, and a certain degree of lithium compensation can effectively suppress the formation of secondary phases caused by lithium deficiency, thereby improving the intrinsic conductivity of the material. Among them, the material prepared under the conditions of a lithium compensation amount of 20 wt%, a pre-sintering temperature of 800 °C, and a sintering temperature of 1300 °C showed the highest bulk conductivity of 3.41 mS/cm at 50 °C, the highest bulk density of material reaching 4.95 g/cm³, which is 98.78% of the relative bulk density of LLTO solid-state electrolyte, and the lowest conductivity activation energy of 0.24 eV for the sample.