Study of Model Electrodes for Li-Ion Batteries (R-5040)

Lithium ion batteries (LIBs) are nowadays widely used in low power applications like consumer electronics. But they have to be improved considerably to fulfill the growing needs in promising fields like electromobility or stationary energy storage technology. For improvements a more detailed knowledge of the basic processes and in particular the structural and morphological changes during battery cycling is highly beneficial. For the anode of LIBs Li alloys with elements like Si, Sn or Al are candidates to replace the currently prevalent graphite electrodes. On the other side Ag or Au react in a similar way forming alloys with Li. Nevertheless detailed characterization of Li alloy structures including metastable intermediate phases at room temperature in general is scarce. The aim is here to get insight in the mechanisms of the anode during charging and discharging using Ionic Liquids as electrolytes. Ionic liquid (IL) based electrolytes enhance the security of the lithium ion battery in comparison to widely used organic electrolytes due to their very low vapor pressure. We intend to observe the Li insertion into the anode's crystal structure. X-ray diffraction (XRD) allows here to in-situ study the complete surface near region of the electrodes at an atomic scale. Structural studies using High Energy XRD offer the great advantage of directly obtaining a slice of the reciprocal space using a 2D detector. The research work includes the development of new electrochemical droplet cells to perform in-situ XRD experiments with ionic liquids. Crystallographic phases including metastable intermediates as well as in favorable cases their orientation relation with respect to the host material will be identified.

Keywords:molecular electronics

Disciplines:Ceramic and glass materials, Materials science and engineering, Semiconductor materials