Electrochemical Analysis of High-Performance Flow-Electrode Capacitive Mixing (F-CapMix) under Different Operating Conditions

• Published in: ACS sustainable chemistry & engineering Vol. 9; no. 28; pp. 9199 - 9208
• Main Authors: Kim, Hanki, Choi, Jiyeon, Jeong, Namjo, Im, Hye-Ji, Yeo, Jeong-gu, Jeon, Sung-il, Chun, Won-Gee, Kim, Dong Kook, Yang, SeungCheol
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19-07-2021
• Subjects: flow-electrode; capacitive mixing; salinity gradient power; electrochemical impedance analysis; resistance
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.1c00848

Unlike fixed-electrode-based capacitive mixing (CapMix) cells that are characterized by intermittent power generation, flow-electrode capacitive mixing (F-CapMix) cells show continuous power generation characteristics owing to the continuous flow of the electrode in the unit cell. F-CapMix cells can be operated in two modes, depending on whether the feed water is fresh water or seawater. In this study, the F-CapMix cell was operated under the fresh-water-based flow-electrode/salt water mode (FFW) and the salt-water-based flow-electrode/fresh water mode (FSW). Under the FFW mode (∼0.175 W/m2), the F-CapMix cell showed a higher power density of 6.7% than under the FSW mode (∼0.164 W/m2). Additionally, impedance analysis based on various flow-electrode and feed water flow conditions under both the modes showed that the higher power density of the F-CapMix cell could be attributed to its lower non-ohmic resistance (i.e., lower charge transfer resistance via the ion-exchange membrane) in the FFW mode than in the FSW mode.