Influence of sintering temperature on conductivity and mechanical behavior of the solid electrolyte LATP

To warrant long-term reliability for application of electrolytes in solid state batteries also mechanical properties have to be considered. Current work concentrates on Li1+xAlxTi2-x(PO4)3 (LATP), which based on its conductivity is a very promising material. Effect of sintering temperature (950, 1000, 1050, 1100 °C) on mechanical properties and conductivity was tested. Impedance tests were carried out and as main focus of the work the mechanical behavior of LATP samples was determined. The impedance tests results revealed that LATP sintered at 1100 °C had the highest ion conductivity. The LATP sintered at 1100 °C revealed also the highest elastic modulus and hardness, which appeared to be related mainly to a smaller lattice parameter with additional effects of lower porosity especially when tested at higher loads. The results indicate that enhancement of both mechanical behavior and conductivity requires lowering secondary phase content and densifying the microstructure of the material.