Lithium aluminum titanium phosphate (LATP) is one of the most promising candidates of solid-state Li-ion conductors for use in electrochemical energy storage . For addressing possible micro-crack formation after sintering, we analyzed the sintering behavior, phase formation, microstructure and ionic conductivity of Li<sub>1.5</sub>Al<sub>0.5</sub>Ti<sub>1.5</sub>(PO<sub>4</sub>)<sub>3</sub> synthesized by solution-assisted solid-state reaction using different NO<sub>x</sub>-free precursors . The sintering temperature strongly influences not only the total conductivity but also the bulk conductivity. It was observed that the crystallinity and long-range order determine the bulk ionic conductivity of the LATP electrolyte. In summary, the crystallinity, phase purity and homogeneity range are the main factors dominating the bulk transport and the microstructure dictates the grain boundary conductivity. Despite high density, micro-cracks were avoided for sintering temperatures below 1000 °C.
 F. Zheng, M. Kotobuki, S. Song, M.O. Lai, L. Lu, J. Power Sources 2018, 389, 198-213.
 B. Davaasuren, F. Tietz, Solid State Ionics, 2019, submitted.