Synthesis and Electrochemical Properties of LATP-LLTO Lithium Ion Conductive Composites

In order to improve the ionic conductivity of NASICON-type lithium ion conductor, Li1.3Al0.3Ti1.7(PO4)3 (LATP), lithium ion conductive composites have been prepared to disperse the perovskite-type lithium ion conductor, Li0.348La0.55TiO3 (LLTO), in the LATP matrix. X-ray powder diffraction revealed that the added LLTO has reacted with LATP to form some LaPO4 derivatives after the sintering at 1000°C. The measured conductivity of the composite increases with the amount of added LLTO up to 4 wt% showing the highest value of 7.6 × 10−4 S cm−1, which is approximately three times larger than that of pristine LATP. Further amount of LLTO addition gives gradual decrease in conductivity due to the deterioration of sintered density. It is also confirmed that the transport number of lithium ion is almost unity for the LATP-LLTO composite from the DC conduction experiments using blocking electrode.