Improving the Ionic Conductivity of Li1+xAlxTi2-x(PO4)3 in a Solid-State Synthesis by Regulating Li-O Bond with B3+ and Y3+


 Li1+xAlxTi2-x(PO4)3 (LATP) is a promising solid electrolyte owing to its high stability and ionic conductivity. But the ionic conductivity of LATP prepared by a conventional solid-phase method is usually one order of magnitude lower than the one prepared by the liquid-phase method. Herein, we achieve a high ionic conductivity of 1.2 mS·cm-1 by doping B3+ and Y3+ ions in LATP in a solid-state synthesis, and the roles of the dopants are revealed. The incorporation of B3+ and Y3+ in the lattice broadens the ion migration path and mitigates the Li+ migration energy barrier. On the other hand, the strong electrostatic interaction between B-O and Y-O bond weakens the electrostatic attraction between the Li-O bond, which makes the Li-O bond easier to break, and greatly improves the ion conductivity of LATP. This study sheds light on the facile solid-state synthesis of LATP with a high ion conductivity and accelerates the incoming practical application in the solid-state battery.