Research
Physical chemistry of solids connects solid state physics and solid state chemistry. In solid state physics the electronic properties of solids and their application or use play the major role. In solid state chemistry traditionally the synthesis and the structural characterisation dominate.
The aim of physical chemistry of solids is the understanding of chemical reactions in and of solids – i. e. the reactivity of solids – by the use of physical methods and concepts (quantum chemistry, spectroscopy, solid state physics, etc.). The most prominent problems and fields within physical chemistry of solids are today:
- Corrosion
- Heterogeneous catalysis and surface chemistry
- Energy storage/-transformation (fuel cells, batteries, photoelectrochemistry, …)
- Chemical sensors
- Information storage by redox switching
- Transport phenomena (diffusion, migration, permeation, …)
- Size effects (nanoscaled materials)
- Degradation of functional materials
- ...
A key phenomenon in numerous fields and a necessary precondition für the chemical reactivity of solids is atomic mobility – in other words diffusion. The understanding and control of atomic mobility is – both on the atomic scale (dynamics) as also on the macroscopic scale (transport) –a serious constraint for the development of many future technologies. It forms an important element of nearly all projects of our research group.
Our research is focused on physical chemistry of solids in general, with a strong interest in materials for electrochemical energy technologies, their reactions and their long term stability. Driven by the increasing importance of electrochemical energy transformation and storage this topic has expanded in our group during the last years. Still our primary concern is fundamental science, but recently we also started applied research (e. g. projects with BASF SE or with Evonik/Degussa AG). We concentrate on inorganic functional materials, their controlled synthesis by physicochemical methods (e. g. pulsed laser deposition), their modification by doping or surface design, the understanding of their properties on the basis of structure and defects and their stability under the influence of external forces. In view of the desired long operation time of modern energy transformers and storages the study of materials stability and degradation gains importance – in particular in the case of nanostructured materials. Since a few years we also investigate electrochemical applications of ionic liquids, e. g. for the deposition of nanoscale particles.
In essence, all our projects center on the interplay of atomic or ionic motion in inorganic (non-metallic) solids with external driving forces – like chemical or electrical potential gradients, temperature gradients or magnetic fields. A typical problem is the controlled application of electric fields for the manipulation or modification of ion- and electron-conducting solids. Materials or compounds under consideration are typically ion- or mixed conducting oxides, oxinitrides, chalcogenides and halides.