Stress Development of Li-Ion Battery Anode Slurries during the Drying Process

Abstract

The effect of sodium carboxymethyl cellulose (CMC) and styrene butadiene rubber (SBR) on film formation was evaluated by analyzing both drying stress and pore size distribution. We discovered that the SBR in a graphite/SBR slurry filled the voids among the graphite particles with the increase in SBR concentration. In addition, the CMC in the graphite/CMC slurry was adsorbed onto the graphite surface, which caused the graphite particles to coalesce. In the graphite/CMC/SBR slurry, a large amount of SBR was needed to increase the mechanical strength of the film in the low concentration region of CMC. However, in high concentration region of CMC, the SBR did not affect the mechanical strength of the film any longer. On the basis of the drying stress measurements, we could draw a processing window map that clearly shows the effect of CMC and SBR on the mechanical strength of the film, which will be useful in the design of anode slurries.