Enhanced capacitive deionization performance with carbon electrodes prepared with a modified evaporation casting method

• Electrode is prepared by evaporating the precursor mixture on a conductive substrate.
• Promising mechanical stability, porosity and hydrophilic property.
• A specific capacitance of 14.5 F/g and a desalination efficiency of 50.4%.
• CDI unit has a regeneration time of 19 min and an electrosorptive capacity of 14.4 mg/g.

A carbon electrode was fabricated with a newly developed evaporation casting method to enhance the desalination performance of a capacitive deionization (CDI) system. The surface and structural properties, as well as the electrochemical behaviors of the prepared electrode were systematically characterized by digital photo images, contact angle measurement, scanning electron microscopy (SEM) and cyclic voltammetry (CV). Capacitive deionization experiments were carried out at various operating conditions using a CDI cell with the as-prepared carbon electrodes. The specific capacitance of the carbon electrode and the desalination efficiency of the CDI cell were14.5 F/g and 50.4% respectively, which are promisingly higher than that obtained with other carbon electrodes prepared with traditional spray coating and roller coating methods. Moreover, a regeneration time of 19 min and an electrosorption capacity of 14.4 mg/g were achieved for capacitive deionization in 25 mL NaCl aqueous solution with an initial conductivity of 2020 μS/cm by using the new carbon electrodes. The enhanced CDI performance was attributed to the loose structure and favorable channels of the carbon electrode, which were formed in a controllable fabrication manner with the modified evaporation casting method. Therefore, the prepared electrodes by using this novel method show promising stability, high porosity, good pore distribution, and favorable hydrophilic property.

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