Influence of microstructure and AlPO4 secondary phase on the ionic conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid state electrolyte
A ceramic solid state electrolyte of lithium aluminum titanium phosphate with the composition of Li1.3Al0.3Ti1.7(PO4)3 (LATP) was synthesized by a sol gel method using a pre dissolved Ti source. The annealed LATP powders were subsequently processed in a binder free dry forming method and sintered under air for the pellet preparation. Phase purity, density, microstructure as well as ionic conductivity of the specimen were characterized. The highest density (2.77gcm 3) with an ionic conductivity of 1.88x10 4 Scm 1 (at 30C) was reached at a sintering temperature of 1100C. Conductivity of LATP ceramic electrolyte is believed to be significantly affected by both, the AlPO4 secondary phase content and the ceramic electrolyte microstructure. It has been found that with increasing sintering temperature, the secondary phase content of AlPO4 increased. For sintering temperatures above 1000C, the secondary phase has only a minor impact, and the ionic conductivity is predominantly determined by the microstructur.