Evaluating Microstructure and Transport within Flow Electrodes for Capacitive Deionization

Abstract

Flow electrode capacitive deionization is a emerging approach for electrochemical desalination. It mitigates several challenges associated with film or membrane capacitive deionization through transforming the electrodes from a static electrode into a suspension electrode. This enables greater surface area, and by consequence higher saline water treatment. The major disadvantage associated with flow electrode capacitive deionization is the high cell resistance and pumping energy. Electrodes with high weight percent minimize resistance but maximize pumping energy, and conversely low weight percent electrodes have reduced pumping energy but increased whole cell resistance. Here, we will present structure-property relationships relevant for static and flowing flow electrodes. The structure-property relationships are obtained through reconstructing the 3-D structure using x-ray tomography[1]. these relationships are then used to predict desalination performance in a bench scale desalination cell. [1]Hatzell, K. B., Eller, J., Morelly, S. L., Tang, M. H., Alvarez, N. J., & Gogotsi, Y. (2017). Direct observation of active material interactions in flowable electrodes using X-ray tomography. Faraday discussions, 199, 511-524.