Synthesis and Characterization of Lithium-Ion Conductive LATP-LaPO₄ Composites Using La₂O₃ Nano-Powder

LATP-based composite electrolytes were prepared by sintering the mixtures of LATP precursor and La₂O₃ nano-powder. Powder X-ray diffraction and scanning electron microscopy suggest that La₂O₃ can react with LATP during sintering to form fine LaPO₄ particles that are dispersed in the LATP matrix. The room temperature conductivity initially increases with La₂O₃ nano-powder addition showing the maximum of 0.69 mS∙cm^-1 at 6 wt.%, above which, conductivity decreases with the introduction of La₂O₃. The activation energy of conductivity is not largely varied with the La₂O₃ content, suggesting that the conduction mechanism is essentially preserved despite LaPO₄ dispersion. In comparison with the previously reported LATP-LLTO system, although some unidentified impurity slightly reduces the conductivity maximum, the fine dispersion of LaPO₄ particles can be achieved in the LATP-La₂O₃ system.