Improved Desalination Performance of Flow- and Fixed-Capacitive Deionization Using Redox-Active Quinone

Capacitive deionization (CDI) has newly emerged as a desalination technology because of its energy and cost effectiveness. In particular, CDI using flow electrode (FCDI) significantly increased salt removal by continuous even at concentrations both brackish seawater. Since mainly uses the electrosorption ions onto an electric double layer on electrodes, carbon materials their derivatives have been widely used. Even with various approaches, including modification synthesis new carbon-based materials, salt-removal capacity FCDI is still limited accessible surface area charge-transfer properties electrodes. Hydroquinone (HQ) redox-active organic molecule highly reversible in electrochemical reactions low-cost non-toxic material. this study, we introduced quinone activated (AC) electrodes for systems. It exhibited significant increase performance (for CDI, more than 65% 300 mM HQ, FCDI, 19% 500 HQ). though specific HQ-added AC reduced penetration small HQ molecules into pores surface, pseudocapacitive contribution from benzoquinone (BQ) performance. We analyzed such cyclic voltammetry impedance spectroscopy. expect that approach will open door realizing excellent saline water, seawater, strong potential large-scale energy-storage Figure 1