Extrusion-Based Processing of Cathodes: Influence of Solid Content on Suspension and Electrode Properties

The influence of the solid content is investigated for cathodes with nickel cobalt manganese oxide (NCM) as an active material during the continuous dispersion in a twin-screw extruder as well as during the coating and drying processes. Rheological and particle size distribution analyses are carried out to characterize the suspensions. Specifically, mechanical, structural, and electrochemical properties of the manufactured electrodes are determined. The presented results show that an increase in the solid content of the electrode suspension during the extrusion process results in a higher carbon black (CB) dispersion degree due to a higher energy input. At solid content above 80 wt%, delamination of conductive graphite and deposition of CB onto the active material occur. Furthermore, it is proved that within a range of 70-75 wt% solid content, the mechanical, conductive, and electrochemical performances can be enhanced.