Effects of Brownian diffusion on dynamics of concentrated suspensions of ideally conductive particles in an electric field

Employing a concentrated suspension of small conductive particles such as a carbon slurry has gained a growing interest in various energy storage and desalination applications, including flowable battery electrodes, and flow-based capacitive deionization. The performance of these systems depends highly on particle concentration and size in the slurry. To this end, we use a large-scale numerical simulation to study the dynamics of ideally conductive Brownian particles in a suspension placed in a uniform electric field. In this system, the particles undergo a non-linear electrokinetic phenomenon termed as dipolophoresis (DIP), which is the combination of dielectrophoresis and induced-charge electrophoresis, as well as Brownian diffusion. Here, the effects of particle size and concentration are presented. The particle size is expressed as Péclet number (Pe), a ratio of the particle motion due to the electrokinetics and Brownian diffusion. Our previous study shows the non-trivial behaviors at concentrated DIP suspensions, such as an increase in suspension diffusivity. It appears that the Brownian effect diminishes these behaviors, and its predominance occurs at Pe < 5, which will be further discussed.