Project Details
Projekt
Theoretical studies on the ion migration through crystalline materials
Applicant
Professor Dr. Timo Jacob
Subject Area
Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 428906592
Migration and diffusion of ions or atoms on a surface or in solids is important for our fundamental understanding of mobility as well as for various applications from energy storage to fuel cells, membranes, polymers, sensors and many others. While various experimental methods have already been developed to obtain atomically-resolved information about the movement and transport of ions, theoretical modelling is often restricted to very limited and idealized model systems. However, in order to investigate the full complexity of ion transport in realistic materials, a multiscale approach is needed, which allows describing migration processes as a function of concentration and also covers structural diversities, e.g. defects, dopants, or grain boundaries. In this project, the relationship between the structure (and composition) and the transport behavior of cationic species in crystalline perovskites, in particular STO as a model system, will be studied, with the aim of resolving the complex energy landscape in these solids. Our previous work on bulk-STO and symmetric grain boundaries will now be continued and extended. On the one hand, the transport of different alkali cations in Nb- and Fe-doped STO will be examined and, on the other hand, different grain boundaries and dislocations will be investigated. Using different theoretical methods (DFT+U, ReaxFF, ML-FF up to kMC) the structure of the grain boundaries and dislocations will first be resolved in close cooperation with the experimental groups (P4-Jooss, P3-Volkert and P8-Gottfried). Together with the CAIT experiments in project P1 and the APT concentration profiles of P3, the ion transport in these systems will then be investigated. Finally, we will perform kinetic Monte-Carlo simulations in order to follow the CAIT experiment (P1 Weitzel) on larger time- and length-scales, where ion migration is induced by a concentration gradient. Again, the outcome will be readily comparable to the experiments performed in P1 (Weitzel) and the structural analyses of P3 (Volkert), P4 (Jooss) and P2 (Vogel).
DFG Programme
Research Units
