Property Modeling for Solid Electrolite and Electrode Materials for All-Solid-State Batteries
In contrast to established lithium-ion batteries, solid-state batteries employ solid electrolytes to reach enhanced energy-density values and to avoid critical failure processes, which can lead to fires.
However, such battery concepts require a stronger attention to mechanical properties, since cell components may deform during charging and discharging processes. We therefore calculate the elastic properties of ceramic solid-state electrolytes and electrode materials in function of their composition by means of ab initio methods, i.e. without using empirical data. At bigger scales, this information will be used to understand possible failure processes related to the formation of conductive paths along grain boundaries.
Degradation of High-Temperature Fuel Cells and Electrolyzers
High-temperature oxide cells play and important role for the production and transformation of green hydrogen. For the long-term stability of such cells, a fundamental understanding of the degradation processes is essential. Our team investigate on the thermodynamic-cinetic level how evaporation transitions and reactions lead to precipitation in the cell components, which can cause loss of performances. Such models are complemented by ab initio investigations to capture at atomic level the underlying processes. The so-obtained data are incorporated in mesoscopic investigations, where we use phase-field methods model the oxidation behavior of interconnection steels. Machine-learning methods are also employed for the optimization of established materials, in order to identify potentially suitable material compositions.
Phase Formation in Metallic Alloys
Our team develops phase-field models for the microstructure development, which plays a central role for example in steels. Building on the thermodynamic descriptions, these models serve to describe the dynamics of interfacial motion. Building on thermodynamic descriptions, these models serve to describe the dynamics of the interfacial motion. Since the resulting microstructures are often very complex, an explicit time tracking of the interfaces is not possible, which is avoided by the phase field method. However, the challenge here is to formulate the models in such a way that they lead to quantitative results that are not falsified by numerical effects. The methods we have developed are applied, for example, to solidification processes and solid phase transformations in metallic alloys.