Ring, J. (2019). On the electrochemical properties of Li-ion conducting Li7La3Zr2O12 and its utilization in all solid state Li-ion batteries [Diploma Thesis, Technische Universität Wien]. reposiTUm. https://doi.org/10.34726/hss.2019.65040
E164 - Institut für Chemische Technologien und Analytik
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Date (published):
2019
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Number of Pages:
75
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Keywords:
Lithium ion battery; solid electrolyte; ion conduction
en
Abstract:
In this work, the impact of field stress on Li7La3Zr2O12 (LLZO) polycrystalline pellets and single crystals was investigated. Voltages of up to a few V were applied using metal electrodes at elevated temperatures in different gas atmospheres (argon and air). The electrochemical processes induced by field stress were investigated by a combination of impedance spectroscopy and chemical analysis. Local conductivities were determined using circular thin film micro-electrodes prepared by photolithography and ion-beam etching. Laterally resolved elemental compositions of the samples were measured by laser-induced breakdown spectroscopy (LIBS). The correlation between changes in electrical properties and chemical composition is discussed. Moreover, electrochemical properties of Li containing oxide thin film electrodes on LLZO were investigated by means of impedance spectroscopy and DC-cycling. In order to prepare such electrodes (e.g. LiMn2O4 and Li4Ti5O12) a RF sputtering device was built and tested for different materials. Influence of the substrate temperature on the properties of the thin films were investigated. All solid state cells were built with Ta-doped LLZO single crystals and polycrystals and reversible electrochemical (dis)charging of the oxide electrodes was demonstrated.
