Understanding the processability of graphite blend electrodes with silicon nanoparticles

Abstract

The manufacturing process aims to optimize the parameters leading to enhanced Lithium-Ion Battery (LiB) electrode properties. Particularly, developing silicon/graphite blends could be an alternative for boosting LiB energy density while using the longstanding properties of graphite. Here, we report the manufacturing parameters impact of the mixing, coating, and calendering steps on the properties of silicon/graphite blend electrodes. The mixing process was assessed by the solid and silicon content dependency, where the viscosity increases when increasing the solid and decreasing the silicon content. Moreover, the slurry rheology directly impacts the mechanical stability of the electrode when coating using thicker comma gaps. The calendering step evidences a porosity threshold necessary for adequate ionic resistance and cycling life. We found that porosities between 45% to 56% for these silicon/graphite blends yield higher performance. Lower than 30% porosity highly impacts the electrochemical performance in a detrimental way.