Effects of Current Collector Shape and Configuration on Charge Percolation and Electric Conductivity of Slurry Electrodes for Electrochemical Systems

Abstract

Flowable slurry electrodes have been used in different energy storage systems as they offer higher flexibility than solid electrodes. In flowable electrodes, mass, momentum and charge transfer coincide with interactions between particles and between particles and the current collectors, and it is almost impossible to investigate these effects experimentally. We present a novel CFD-DEM approach including the phenomena of partial charge transfer to model the effects of contact and electrolyte resistances, and to investigate the impacts of using different current collector shapes and configurations on percolation threshold and electric conductivity of slurry electrodes. Our results show that, with a perpendicular current collector configuration, the conductivity of slurry electrodes increases with higher velocity, while with a traditional parallel configuration, it decreases when the velocity is increased. Additionally, we demonstrate that the current collector configuration significantly affects the percolation threshold in slurry electrodes, and, importantly perpendicular configuration expedites the formation of a conducting network in flowing slurry electrodes. Furthermore, the effects of using (HTAB) surfactant on the conductivity of slurries is investigated experimentally. We observed that the use of surfactant decreases the conductivity of slurries by roughly 10%, which is negligible compared to the advantages in terms of slurry stability and flowability.