Synthesis, microstructure and ionic conductivity of Li1+xAlxTi2-x(PO4)3-based composite ceramic electrolyte

NASICON-type Li1+xAlxTi2-x(PO4)(3) (LATP) solid electrolyte features low cost of raw materials, high stability against O-2/H2O, high ionic conductivity and high compatibility with cathode. Despite these merits, the direct contact of Li with LATP would trigger the reduction of Ti4+ into Ti3+, and thereupon decrease ion conductivity and enhance electron conductivity, thus limiting its application. In this work, the garnet Li(6.5)La(3)Zr1.5Ta(0.5)O(12) (LLZTO) particles were chosen to disperse in NASICON-type Li1.3Al0.3Ti1.7(PO4)(3) matrix in order to strengthen stability against Li metal. During sintering, the matrix/particle reaction occurs, where LLZTO reacts with LATP, inducing the formation of LaPO4 particles. By optimization of LLZTO content, an enhanced ionic conductivity of 1.03 x 10-3S cm(-1) can be harvested. Moreover, introducing LLZTO particles into LATP matrix can slow down the degradation of the electrolyte to a certain extent and provide better interfacial stability of symmetrical battery than pure LATP solid electrolyte.

Automated summary

In this study, the stability and ionic conductivity of the NASICON-type Li1.3Al0.3Ti1.7(PO4)(3) electrolyte were enhanced, and the degradation of the electrolyte was slowed down by introducing LLZTO particles.