Influence of the mixing speed in the rheology of NMC622-based Li-ion battery electrode slurries

Abstract

Finding a correlation between the rheology of an electrode slurry and the mixing variables is challenging due to the complex interactions among the materials in the suspension. Here, we report a systematic study of the mixing speed and how this variable impacts the slurry rheology of the Nickel Manganese Cobalt Oxide (NMC622) positive electrode at 2000, 3000, and 4000 rpm and maintaining constant the other mixing parameters. We partially combined the slurry components and compared the rheology results with the complete formulation. This systematic study shows differences in viscosity depending on mixing speed and the slurry component combination. In addition, frequency oscillatory sweeps were used to obtain information on the slurry microstructure, showing changes depending on the nature of component interactions. The slurries were also casted, dried, and calendered. Numerical simulations were also performed to analyze the experimental findings. Understanding the slurry rheology and the interaction of the formulation components is fundamental for further engineering electrode manufacturing and analysis of the dried electrode's output properties.