Paper Number
SC51 

Session
Suspensions and Colloids

Title
Obtaining structural information of carbon black in carbon black/polymer suspensions with rheo-dielectric measurements

Presentation Date and Time
October 12, 2022 (Wednesday) 4:45

Track / Room
Track 1 / Sheraton 4

Authors (Click on name to view author profile)

1. Liu, Qingsong (Northwestern University, Chemical and biological engineering)
2. Richards, Jeffrey J. (Northwestern University, Chemical and biological engineering)

Author and Affiliation Lines (in printed abstract book)
Qingsong Liu and Jeffrey J. Richards
Chemical and biological engineering, Northwestern University, Evanston, IL 60208

Speaker / Presenter 
Liu, Qingsong

Keywords
experimental methods; colloids; suspensions

Text of Abstract
Lithium-ion battery technology plays a central role in the wide-spread adoption of renewable energy and electrical vehicles due to improved large-scale manufacturing techniques. To further improve the performance and reduce the cost of lithium-ion batteries, a fundamental understanding of the relationships linking battery performance to the structural characteristics of the battery components is required. In particular, the lithium-ion battery porous electrode has a complex microstructural structural hierarchy that depends sensitively on how it is processed. The origin of the process sensitivity of porous electrodes is the presence of high structured carbon blacks (CBs) used as conductive additives. Controlling electrode structure during processing requires understanding the structure of CB agglomerates that form in the coating fluid in response to deformation (such as shear) and the influence of other slurry components such as the polymer binder poly(vinylidene difluoride) (PVDF). We used rheo-dielectric measurements to show that the addition of PVDF modifies the structure of CB agglomerates through the indirect effect on the solvent viscosity. Simultaneous impedance 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 impedance measurements. We anticipate that this finding will chart a pathway towards a framework of predicting dielectric properties of such suspensions from their rheological properties.