Simon Kammler


Synthesis and characterization of iron substituted garnet type solid state electrolytes for lithium ion batteries

Fig. 1: Scheme of a sol gel synthesis Copyright: S. Kammler Fig. 1: Scheme of a sol gel synthesis

In the course of the ongoing mechanization of our society and the advancing energy transition, safe, efficient and environmentally friendly energy storage systems are increasingly moving to the fore.

Electrical energy is currently stored mainly in lithium ion batteries, whose latest generation incorporates organic liquid or polymeric electrolytes. These electrolytes however have several safety-relevant and ecological disadvantages like combustibility and toxicity.

Inorganic solid state electrolytes provide higher safety at simultaneous improved environmental compatibility. Suitable materials, amongst others, are garnet type structured materials like Li7La3Zr2O12, which provides a good lithium ion conductivity of 10-3-10-4 S cm-1 [1] in its through iron substitution cubically stabilized form Li7-3xFexLa3Zr2O12.

For a good ionic conductivity and a sufficient separation of the electrodes, ceramics of high density are required. The density can be influenced by the sintering conditions and the microstructure of the material which is supposed to be sintered.

The aim of this work is therefore the investigation of the sintering behavior and the evolution of the microstructure of cubically stabilized Li7-3xFexLa3Zr2O12 synthesized through sol gel synthesis. The characterization will be carried out through x-ray powder diffraction, thermogravimetric analysis, scanning electron microscopy and dilatometry. The lithium ion conductivity will be determined by electrochemical impedance spectroscopy.

[1] D. Rettenwander, R. Wagner, J. Langer, M.E. Maier, M. Wilkening, G. Amthauer, Eur. J. Mineral. 2016, 28, 619-629.