<p dir="ltr">Lithium-ion batteries (LIBs) are at the forefront of the energy storage technology for portable electronic devices and are playing a pivotal role in vehicle electrification. As the conventional LIBs consisting of a graphite anode and a transition metal oxide cathode approach their theoretical energy density limits, significant research efforts are being made towards developing next-generation batteries that can meet the ever-increasing energy density demands. In this regard, solid-state batteries (SSBs), employing lithium metal anode and a composite cathode, have garnered significant attention as a promising alternative to conventional LIBs, offering enhanced energy density and safety. However, the development of stable, high-performance SSBs is hindered by several interfacial and chemo-mechanical challenges due to solid-solid nature of interfaces. Limited solid-solid contact between the interacting species leads to severe transport and reaction limitations, which exacerbate during cycling due to progressive delamination at the interfaces. Such a phenomenon also results in current constriction at the remaining point contacts, which ultimately leads in the formation of electrochemical and mechanical hotspots within the SSB, impacting both the rate capability and cycling performance.</p><p dir="ltr">In this thesis, a comprehensive mesoscale investigation of solid-state battery (SSB) cathode architectures will be presented, elucidating the complex interplay between microstructure, kinetic-transport interactions and chemo-mechanical coupling. By examining the key limiting mechanisms that manifest at various SSB cathode microstructural regimes, a mechanistic design map highlighting the dichotomy in reaction and ionic/electronic transport limitations will be established. The impact of cathode microstructural heterogeneity on spatio-temporal dynamics, thermo-electrochemical behavior, and lithium metal anode stability will be revealed. In addition, the impact of stack pressure on solid-state cathode performance will be studied and how stack pressure influences the microstructure-dependent reaction and transport interactions will be delineated. Lastly, this thesis will investigate crystallographically oriented dense cathode architectures for high energy density SSBs, providing critical insights into their performance limitations and potential pathways for optimization. Overall, the dissertation will focus on the fundamental insights into the mesoscale behavior of the solid-state cathodes and establish the mechanistic pain points and design guidelines for consideration in the future development of improved SSB cathode architectures.</p>

Im Rahmen der Qualitätsentwicklung und -sicherung von Unterricht wurden in den letzten zwei Jahrzehnten auf Bundes- und Länderebene auch Maßnahmen zur Professionalisierung von Lehr-personen festgelegt. Vor diesem Hintergrund begannen 2012 am Deutschen Zentrum für Lehrerbildung Mathematik (DZLM) auch Arbeiten, um bestehende Fortbildungsangebote für Grundschullehrkräfte zu erweitern. In dieser Arbeit wird das Konzept einer Stochastik-Fortbildung für Lehrpersonen, die Mathematik in der Grundschule unterrichten, vorgestellt. Die Entwicklung greift Forschungserkenntnisse zum Verständnis von professioneller Kompetenz von Lehrpersonen und zur Gestaltung von Professionalisierungsprozessen auf und bindet konzeptionell Impulse für Unterrichtsentwicklungsprozesse ein. In fünf Kursdurchführungen wurde das Konzept realisiert und hinsichtlich seiner Umsetzbarkeit untersucht. Die in diesem Rahmen gewonnenen Daten von 120 Lehrpersonen geben detailliertere Einsichten in Entwicklungsprozesse unterschiedlich qualifizierter Lehrpersonen. Die Ergebnisse zeigen insbesondere, dass in der fachinhaltlich orientierten Fortbildung ein fachlicher und fachdidaktischer Wissenszuwachs erreicht werden kann. Die Defizite bezüglich einer mathematischen Grundausbildung eines Lehramts können bei Lehrpersonen, die Mathematik fachfremd unterrichten, auf diesem Weg aber nicht überwunden werden. Die Untersuchungen zeigen zudem, dass die qualifikationsheterogene Zusammensetzung der Kursgruppen die Durchführung und das Lernen der Lehrpersonen bereichern. Mit der Einbindung des Konzepts der Professionellen Lerngemeinschaft (PLG) in den Kurs und Erprobungen in den Praxisphasen gelingt es, Impulse für Unterrichtsentwick-lungsprozesse zu geben. Diese Fortbildung kann ein berufsbegleitender Baustein in der Ausprägung von Lehrkräfteprofessionalität sein und den lang andauernden Prozess der Konstruktion und Selbstkonstruktion des Berufs unterstützen. / In the past two decades, increasing the quality of mathematics teaching and learning, particularly fostering the professional knowledge and skills of teachers has been researched in depth. Before this background, the German Center for Mathematics Education (Deutsches Zentrum für Lehrerbildung Mathematik, DZLM) started from 2012 onwards to offer professional development (PD) courses for teachers and facilitators. This thesis presents a concept for a PD course on stochastics for primary teachers, which draws on recently gained empirical evidences on appropriate professional competencies and on design elements relevant for effective professionalization. The concept of the PD course also includes building professional learning communities (PLCs) to initiate teachers´ ongoing professional growth through working collaboratively on improving their classroom practices. The long-lasting PD course has been conducted five times and data was gained to evaluate the feasibility of the concept. That is, the data acquired from 120 teachers provided detailed insight into the personal development of teachers with different qualifications, including those teaching out-of-field. The results show that a PD course focusing on a certain subject leads to an increase of both content knowledge professional content knowledge. However, deficits due to a missing basic education in mathematics - as for teachers not specialized on mathematics - cannot be totally overcome by this PD course. However, the results indicate that the heterogeneous teacher groups possessing different qualifications enrich the learning processes of all participants. Including the PLC concept into the PD course and conducting practical phases to probe issues in the classroom were both decisive impulses helping teachers to further develop their practices. Thus, the PD course proved to be effective with respect to fostering teachers´ professional knowledge and skills sustainably and contributed to teachers´ life-long and ongoing learning.