Physikalische Chemie I

Oxides play an ever increasing role as advanced functional materials. Examples are tarnishing layers during high temperature oxidation, oxygen ion conducting oxides in high temperature fuel cells, mixed conducting oxides in oxygen permeation membranes, lithiumoxides for batteries, high temperature superconductors, ferroelectrics, catalysts etc. The oxides that are used are complex oxides, i.e. they contain normally several cations and they exist in complicated crystal structures with several sublattices. The properties of these oxides are determined to a large extent by the thermodynamics and kinetics of point defects. Basic research concerning defect chemistry, transport properties and chemical reactivity is the basis for the improvement and optimization of functional materials.

In our research we are using the following techniques:

Thermogravimetry in situ X-ray diffraction in situ X-ray absorption spectroscopy Radiotracer diffusion Secondary ion mass spectrometry (SIMS) Electron microscopy with chemical analysis (SEM/EDX) Impedance spectroscopy Computer simulation and modeling Density functional theory

D. The, S. Grieshammer, M. Schroeder, M. Martin, M. Al Daroukh, F. Tietz, J. Schefold, A. Brisse Microstructural comparison of solid Oxyde electrolyser cells operated for 6100 h and 9000 h Journal of Power Sources 275 (2015) 901-911. H. Jang, J. Brendt, L.N. Patro, M. Martin, H.-I. Yoo Unexpected thermoelectric behaviour and immiscibility of the allegedly complete solid solution Sr(Ru1-xTix)O3 Phys.Rev.B 89 (2014) 144107 Y. Aoki, C. Wiemann, V. Feyer, H.-S. Kim, C.M. Schneider, H.-I. Yoo, M. Martin Bulk mixed ion electron conduction in amorphous Gallium oxide causes memristive behaviour Nat. Commun. 5:3473 (2014) T. Leichtweiss, R.A. Henning, J. Koettgen, R.M. Schmidt, B. Holländer, M. Martin, M. Wuttig, J. Janeck Amorphous and Highly Nonstoichiometric Titania (TiOx) Thin Films Close to Metal-like Conductivity Mater. Chem. A 2( 2014) 6631-6640. S. Grieshammer, B.O.H. Grope, J. Koettgen, M. Martin A combined DFT+U and Monte Carlo study on rare earth doped ceria Phys.Chem.Chem.Phys. (2014) Advance Article