Many materials with important properties for a multitude of applications in our daily life are solids that consist of nanocrystalline phases in close association. In this project, the focus is on glass ceramic and battery materials.
The crystal structures defining the physical properties of these materials are often not accessible through methods like X-ray powder diffraction. FAST-ADT [1] , a three-dimensional electron diffraction method (3D ED), includes routines for crystal tracking and already been successfully applied to single crystals around 100 nms in size. Here three dimensional ADT data for crystal structure analysis needs to be acquired from agglomerated nano crystals down to 20 nm in size leading to the need for development of dedicated tracking routines. In addition, these crystals exhibit disorder effects, twinning or superstructures. Based on already available routines for quantitative analysis of stacking faults [2] the analysis of diffuse scattering from 1D defects is the focus.
Batteries with fluoride as transport ion are novel battery systems [3]. Recently, intercalation-based materials with Ruddlesden-Popper type structure have been developed as electrode materials, since they can transform to oxyfluorides A2BO4-yF2y(0 ≤ y ≤ 2). For this class of compounds, the intercalation and de-intercalation of fluoride ions is very often accompanied by structural changes, which are hard to resolve in detail by X-ray powder diffraction methods only. This is due to the use of composite electrodes with solid electrolytes comprised of strong X-ray scatterers. Lately, electron diffraction was used to resolve such structural changes in more detail [4], which will be elaborated further in the advertised project.
Glass ceramics are materials consisting of a glass phase and one or more crystalline phase. They are produced by heat treatment of a precursor glass leading to the growth oft he crystalline phases. Depending on the used glass system and the heat treatment parameters glass ceramics have a wide array of applications ranging from bioactive glass ceramics over optical applications to host matrices for radioactive nuclear waste[5].
[1] S. Plana-Ruiz, Y. Krysiak, J. Portillo, E. Alig, S. Estrade, F. Peiró, U. Kolb, Ultramicroscopy 2020, 211, 112951. [2] Y. Krysiak, B. Barton, B. Marler, R.B. Neder, U. Kolb, Acta Cryst A 2018, 115, 41-49. [3] M. A. Nowroozi, I. Mohammad, P. Molaiyan, K. Wissel, A. R. Munnangi, O. Clemens, Journal of Materials Chemistry A 2021, 9, 5980-6012. [4] M. A. Nowroozi, K. Wissel, M. Donzelli, N. Hosseinpourkahvaz, S. Plana-Ruiz, U. Kolb, R. Schoch, M. Bauer, A. M. Malik, J. Rohrer, S. Ivlev, F. Kraus, O. Clemens, Communications Materials 2020, 1, 27. [5] A bright future for glass-ceramics, American Ceramic Society Bulletin2010, 89(8), 19.