Effect of microstructure and surface impurity segregation on the electrical and electrochemical properties of dense Al-substituted Li7La3Zr2O12

Al-substituted Li7La3Zr2O12 (LLZO) pellets with a grain size of 100–200 μm and a relative density of 94% were prepared by conventional solid-state processing at a sintering temperature of 1100 °C, 130 °C lower than previously reported. Morphological features and the presence of impurities were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Femtosecond Laser Induced Breakdown Spectroscopy (LIBS) was used to visualize the distribution of impurities. The results suggest that chemical composition of the powder cover strongly affects morphology and impurity formation, and that particle size control is critical to densification. These properties, in turn, strongly affect total ionic conductivity and interfacial resistance of the sintered pellets.