Low temperature synthesis of Li0.33La0.55TiO3 solid electrolyte with Al3+ doping by a modified Pechini method

By modifying the preparation process of Pechini method, we can improve the structure of Li0.33La0.55TiO3 (LLTO) crystalline powder, so as to obtain high-density LLTO solid electrolyte. Through optimizing the sintering process, LLTO powder with good dispersion and uniform particle size was calcined at 800 °C; afterwards, the LLTO solid electrolyte samples with excellent properties were prepared by sintering at 1250 °C. The LLTO samples showed a low activation energy of 0.32 eV, a high relative density of 91.2%, and a high ionic conductivity of 2.7 × 10−5 S/cm. By adding three different aluminum salts, the ionic conductivity of Al3+-doped LLTO (A-LLTO) was further improved significantly. Especially in this case, with 30-nm Al2O3 doped, the conductivity of A-LLTO was increased to 4.7 × 10−5 S/cm, the activation energy was reduced to 0.30 eV, and the relative density was increased to 92.8%.