(375i) Obtaining Structural Information of Carbon Black in Carbon Black/PVDF Suspensions with Simultaneous Rheo-Electric Measurements

Lithium-ion battery slurry containing carbon black has a microstructure that depends sensitively on how it is processed due to carbon black’s (CB) evolving structure when subjected to coating flows. While polymer binder polyvinylidene difluoride (PVDF), one of the main components of the slurry, plays an important role in modifying the structure and the rheology of CB, a quantitative understanding of the polymer role under shear is lacking. We used rheo-electric measurements to show that the addition of PVDF modifies the structure of CB agglomerates through the indirect effect on the solvent viscosity. Simultaneous electric measurements were conducted on these CB/PVDF suspensions in shear flow as a function of carbon and PVDF composition. We found that the CB agglomerate size information can be derived from normalized suspension viscosity through rheological measurements. Additionally, the further validation of such size information is evident in the dielectric strength of the relaxation process obtained from the electric measurements. These findings will be valuable to energy storage systems containing CB as the dispersion of CB can be predicted and controlled with tunable processing conditions to optimize the performance. (Published in the Journal of Rheology, 10.1122/8.0000615)