Lithium-ion Batteries combine high energy density with high power density at ever lower costs. That is why they are the benchmark in the field of electrochemical energy storage. They are regarded as a key technology in a number of fields of application, e. g. electromobility and the stabilization of power grids. Our research focuses on the development of electric cars. We also model batteries for the electrical network of satellites, working with foreign space organizations such as JAXA (Japan) and NASA (USA).
In our research area, models for lithium-ion batteries are developed across all technically relevant scales – from molecule to system – along the entire life cycle of the battery – from production to aging behaviour. By combining theory-based modeling, microstructure-resolved simulation and data-driven algorithms, the processes in lithium-ion batteries can be described and optimized in great detail.
Lithium-ion batteries are becoming increasingly important for the energy storage markets. For many applications, however, their energy density, resource consumption and costs are not optimal. That’s why we participate in research on numerous innovative battery designs. Sulphur and air electrodes promise high energy density at low costs and thus offer opportunities for future electromobility. Lithium metal electrodes could significantly increase the energy density of the negative electrode. Novel stable electrolytes such as ionic fluids promise help in the implementation of these concepts.
We are also researching post-lithium batteries. We place a special focus on the development of zinc batteries, which show off their cost advantages, especially for stationary applications. In zinc batteries, high-energy zinc-metal electrodes are combined with low-cost aqueous electrolytes. In the Cluster of Excellence POLiS, we also investigate sodium and magnesium batteries. We are looking at intercalation, sulfur and air electrodes.
Solid state batteries
Solid state batteries are regarded as a great source of hope for the next generation of high-energy cells for electromobility. Their structure and function are similar to conventional Li-ion batteries or lithium-metal batteries. The main difference is the use of solid electrolytes. In particular, two classes of materials are used Differences: I) polymers such as PEO and II) inorganic solid electrolytes such as LLZO or thiophosphates.
From an application point of view, the main advantage of these materials is that they are either flame retardant or non-flammable and more heat-resistant. This is of great importance in terms of safety, especially for use in electric vehicles. It is also expected that this will enable the use of lithium metal at the electrode in the future, which will significantly increase the energy density of the systems.
For the modelling and simulation of both systems we lay the theoretical foundations and investigate first application cases. In particular, we are involved in the Festbatt competence cluster and a German-American initiative for research into solid-state batteries. Within this framework, a number of fundamental questions concerning the materials, methods, models, cell architecture and manufacturing processes used will be addressed in order to prepare for the commercialisation of this technology.