Surface modification of Li₃PO₄ to Li_1.3Al_0.3Ti_1.7(PO₄)₃ by wet chemical process and its sintering behavior

Abstract

The surface modification of lithium phosphate on lithium alumina titanium phosphate (LATP) by a wet chemical method densified the LATP to over 90 % at a sintering temperature of 800 °C. This temperature was approximately 300 °C lower than that of LATP without additives. Densification of LATP with lithium phosphate significantly progressed from 700 to 800 °C, and endothermic peaks corresponding to its melting were found in a similar temperature range, suggesting that the densification mechanism would be due to liquid phase sintering. The liquid phase of Li₃PO₄ is produced by a multi-step thermal decomposition involving the reaction with LATP. The sintered LATP with lithium phosphate showed a density of about 90 % and the highest ionic conductivity of 3.5 × 10⁻⁴ S/cm at 25 °C, suggesting an excellent Li ion conducting, solid electrolyte material.