Nano-grass like AlOOH as an Al source for synthesis of Li1.3Al0.3Ti1.7(PO4)3 solid electrolytes with high ionic conductivity

Abstract

The lithium-ion conductor Li1.3Al0.3Ti1.7(PO4)3 (LATP) is prepared by a solid-state method using nano-grass-like AlOOH as the Al source. The nano AlOOH precursor, obtained by a hydrothermal method, makes it easier for Al atoms to replace Ti atoms in the LiTi2(PO4)3 structure during the solid-state reaction process, which creates a large amount of lithium vacancies and lithium gaps, leading to the easier migration of Li+ ions in the obtained LATP conductor. Moreover, the as-prepared LATP has high crystallinity and high relative density (96.06%), which are beneficial for reducing the grain boundary resistance as well as improving the total ion conductivity. The influences of sintering temperature and holding time on the ionic conductivity and morphology of the LATP conductor are also discussed systematically. The total ion conductivity of LATP reaches to as high as 3.44 × 10-4 S cm-1 when the samples are sintered at 950 °C for 6 h. This work provides a new method for the preparation of LATP with high ion conductivity, which is of great significance for all-solid-state lithium-ion battery application.