Semi‐Dry Extrusion‐Based Processing for Graphite Anodes: Morphological Insights and Electrochemical Performance

Abstract

To improve the sustainability of large‐scale battery production, it is important to find affordable, energy‐efficient processing strategies. Additionally, to achieve electrochemical performances with good rate capability and cycling stability, it is important to understand the link between the processing strategy and the resulting anode morphology. Herein, a novel, low‐solvent, extrusion‐based strategy is employed for the production of graphite anodes. Furthermore, a comparative analysis is conducted between semi‐dry processed electrodes and conventionally manufactured anodes, focusing on structural parameters such as parameter distribution, ionic resistances, and rate capability. Besides, various screw configurations are employed during the semi‐dry process, and it is observed that higher energy input during mixing resulted in an increase in the surface area of the anode. Moreover, it is noted that an increased surface area correlated with enhanced rate capability during cycling. This finding highlights the advantages of employing low‐solvent, extrusion‐based processing methods. Nevertheless, excessively high surface areas lead to an increase in the electrolyte/electrode interface area, resulting in the formation of an undesirable solid–electrolyte interphase that hampers discharge capacity and cycling stability. Hence, it is crucial to strike a balance between the electrode's microstructure, including particle structures, and its electrochemical performance.

Continuous Anode Slurry Production in Twin-Screw Extruders: Effects of the Process Setup on the Dispersion

“…By using wider kneading elements, better dispersion and particle breakage were achieved, especially when using dry binders. Similarly, the significance of the screw configuration was also recently addressed by Wiegmann et al [10] for anodes. The study investigated the extrusion of graphite anode pastes with low solvent content and evaluated different screw configurations.…”