Fluid Transport Properties from 3D Tomographic Images of Electrospun Carbon Electrodes for Flow Batteries

Abstract

Three-dimensional x-ray computer tomography images were obtained of electrospun poly(acrylonitrile) electrodes for a flow battery. The materials were imaged before and after carbonization. Information about the internal morphology; local fiber size and porosity, was analyzed and provided key insights into both the electrospinning and carbonizing processes. It was found that traditional imaging techniques may not be suitable for materials generated through electrospinning as it is a highly dynamic process. The fiber size tended to vary throughout the process while the porosity was relatively constant. Viscous flow was modelled through the material using the Lattice Boltzmann Method and the 3D flow fields that resulted provided further information about the role of heterogenous features on the performance of an electrospun electrode in a flow battery. The local porosity of the material had the largest effect on the material’s flow dynamics.