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In literature, the ionic conductivity of solid electrolytes is often discussed as one of the most important properties of an all solid-state battery. However, the behavior of the electrolyte inside a composite electrode and the influence of electrode structure on the ionic conductivity is neglected in most of the studies. In this work we manufactured model electrodes with clearly defined structures by using electrochemically inert glass particles as model active material with six different volume fractions and four different particle sizes, respectively. Higher volume fractions and smaller particles led to a decrease of ionic conductivity down to two decades due to emerging pores and a rise of tortuosity. Beneath the ionic conductivity the interface resistance between Li-metal and model electrodes was investigated, clearly indicating that high volume fractions of small active materials led to higher interface resistances. Finally, a model is introduced to predict the effective ionic conductivity of a solid electrolyte within an all solid-state battery electrode by just knowing the volume fraction of active material.

A method to determine the agglomerate and aggregate sizes of carbon black (CB), commonly used in anode and cathode suspensions for lithium-ion battery electrodes, is presented. An analysis via light diffraction and scattering was evaluated, and measuring parameters and the development of sample preparation are described in detail. Within this work, different dispersing additives were tested with regard to their ability to stabilize the CB agglomerates and aggregates after dispersing. Furthermore, a sample preparation routine was set up which enables the determination of CB particle sizes in about 10 min. This includes the separation of active material particles and the particle size analysis itself. Furthermore, the method was tested with discontinuously and continuously processed suspensions using a laboratory dissolver and a pilot-scale extruder. In these experiments, the progress of CB deagglomeration in the dispersing step could be proven. For this reason, the method represents a suitable instrument for a quality check in an early production stage.

This work is about the possibility to enhance the lithium ion conductivity of a polymeric solid-state electrolyte via scalable production processes which can directly be utilized for series production. The solid electrolyte consists of PEO, LiTFSI and SiO 2 and achieved a maximum ionic conductivity of σ Ion = 2.4 •10 −3 S cm −1 at 90 °C and σ Ion = 1.26 •10 −3 S cm −1 at 80 °C. For that, we present a scalable completely dry process chain consisting of granulation, plastification and calendering without the need of any solvents. Within these production processes the influence of process parameters like specific energy input, production temperature and filling degree to the properties of the polymeric solid electrolyte components (among others lithium ion conductivity, chain length, density) are investigated. One key finding is that a suitable process window in terms of specific energy input during plastification is very small and can be quantified for the given process geometry. Under-or overshooting these barriers can directly lead to a degradation of the whole system and as a result directly decreased lithium ion conductivities. Besides process parameters, we also investigate material and formulation parameters, like salt concentration, annealing time and measurement temperatures. Finally, a model is presented to describe the maximum achievable lithium ion conductivity as a function of the specific energy input during production.

In almost all state‐of‐the‐art lithium‐ion batteries, the negative electrode is made from graphite. For dual‐ion batteries (DIBs), graphite electrodes can even be used as negative and positive electrodes as the electrolyte provides both cations and anions for energy storage. As the amount of active material is very high in graphite electrodes, one of the main structure‐controlling parameters is its particle size distribution (PSD). Based on changes in the active material particle size and resulting changes in electrode structure, the corresponding cell characteristics like coulombic efficiency or power density are strongly affected. Herein, results for graphite positive electrodes manufactured with different PSDs of one typical commercial synthetic graphite are displayed. A high‐performance single‐wheel air classifier is used to create the differently distributed graphite particle fractions that do not vary in particle shapes for all fractions created. To gain a better understanding of the particle size impact on electrode properties, the electronic and mechanical properties, as well as the electrode structure, are investigated. The electrochemical performance of the Li metal/graphite system is correlated with structure properties influenced by PSD.