Synthesis and sintering of Li1.3Al0.3Ti1.7(PO4)3 (LATP) electrolyte for ceramics with improved Li+ conductivity
Abstract The key material for all solid state batteries is the solid electrolyte. In concepts with high energy density and capacity, this Li+ conductive component has two essential functions: Substituting the liquid electrolyte in the cathode and separating the cathode from the anode. Therefore, the research on Li+ conductive solids is one important step to realize high performing all solid state batteries. In this study, two different methods of preparing Li1.3Al0.3Ti1.7(PO4)3 (LATP) powder are compared with regard to particle size, phase purity and sintering properties. As top down method the melting and as bottom up route the sol gel synthesis are applied. Spark Plasma Sintering (SPS) is used to densify the powders at temperatures between 800 and 1000 degC. The densities, the microstructures and the Li+ conductivities are compared in relation to the preparation method. Using sol gel synthesis, the phase purity of the LATP powder is higher compared to the top down route. The milling of the synthesized powder increases the homogeneity of the resulting microstructure and enhances the ionic conductivity. Room temperature Li+ conductivity of 1 x 10 3 S cm 1 with a high density of 99.4% was achieved with the milled, sol gel synthesized powder at a sintering temperature of 1000 degC.