Membrane Assisted Capacitive Deionization with Binder-Free Carbon Xerogel Electrodes

Abstract

Performance results from the extended operation of CDI and MCDI single cells configured with binder-free mesoporous CX electrodes are presented. A Randle’s equivalent circuit consisting of capacitive and resistive impedances was used to simulate the current response of the CDI and MCDI cells. The CDI cell had a lower initial resistance (R S ) but also a lower resistance to current leakage (R L ), and a lower effective capacitance (C DL ) in comparison to the MCDI cell. The simulation model showed good agreement with experimental data, but overestimated the prediction of R S values. Performance data from conductivity profiles showed improved performance for the MCDI cell, but also inversion spiking for the CDI cell after extended operation. The results suggest that the lower R L , led to faster oxidation of the electrodes and a degraded CDI performance. In contrast, the MCDI cell showed preserved behavior with extended operation.