A capacitive deionization device includes; at least one flow path configured for influent water flow, at least one pair of electrodes, at least one charge barrier disposed between the at least one flow path and a corresponding electrode of the at least one pair of electrodes, and at least one electrolyte solution disposed between the at least one electrode of the at least one pair of electrodes and a corresponding charge barrier of the at least one charge barrier, wherein the at least one electrolyte solution is different in at least one of ionic concentration and ionic species from the influent water.