Capacitive deionization (CDI) is an emerging desalination technology based on the same charge storage principles as in electrical double-layer supercapacitors (EDLC's). In this study, electrodes of differing thicknesses were tested using constant current (CC-CDI) and constant voltage (CV-CDI) operational modes in order to study the best way of sequestering the highest amount of ions under different salt concentration scenarios. CV-CDI was used to calculate electrode time constants (RC) and thereby determine a suitable current density for desalinating the solution. Results showed that the voltage pulse produced a fast but heterogeneous layer of ion adsorption, presumably, on the most accessible part of the electrode surface. Thus, volumetric specific capacitance under CV-CDI mode might vary from 17-24 F cm(-3) and 14-20 F cm(-3) for 50 mu m and 180 mu m electrodes, respectively. Nevertheless, results demonstrated that, under the constant current mode, it is possible to increase charge storage by 30% for a CDI cell consisting of thin electrodes and as much as 80% for thicker electrodes simply by controlling current density and, therefore, the rate capability. Moreover, the analysis of the charge efficiency indicated that a proper selection of the current density can result in efficiencies above 80% regardless the salt concentration scenario. (C) The Author(s) 2018. Published by ECS.