All Solid State Battery cluster "FestBatt", Characterization-platform

The aim of the project is the structural and microstructural characterization of commercial and synthesized
materials, the determination of reaction pathways during the synthesis and the determination of the Li
diffusion pathways on selected solid electrolytes (FE). In addition, a detailed analysis of the electrolytes,
interfaces and composites developed in the material platforms 'Oxides', 'Sulfides' and 'Polymers' is carried
out by means of electrochemical characterization methods. The focus is on electrochemical impedance
spectroscopy and the analysis of the impedance spectra via the distribution function of the relaxation times
(DRT), which make it possible to distinguish power and capacity limiting processes in electrodes and cells
and to quantify them by physicochemical equivalent circuit models. A focus will be placed on the impedance
analysis of polycrystalline FE as well as FE / FE interfaces, a methodology for the quantification of bulk,
grain boundary and interface resistances. The structural characterization of the materials is carried out by
diffraction methods with X-ray, synchrotron and neutron radiation, the data obtained being evaluated by the
Rietveld method. In disordered, semicrystalline and amorphous systems, 'Total Scattering' should also be
used to obtain the pair distribution functions (PDF) and therefore structural information. The obtained
structure and impedance data are made available on the one hand to the platform 'data' for the acquisition
within a database and for the modeling of promising materials. On the other hand, the results will be
incorporated directly into the optimization and adaptation of the process and synthesis routes of the
material platforms. Tomographic methods (FIB / SEM and X-ray tomography) support the interpretation of
the measurement data on the 3D imaging of multiphase electrodes and the characteristic microstructural
parameters derived from them.