The electrode materials in flow‐electrode capacitive deionization desalination: a mini review

Abstract Flow‐electrode capacitive deionization (FCDI) is a newly developed desalination technology with a high electrode loading for superior salt removal efficiency, even with high feed salinity. However, the improvement in FCDI performance could be restricted by obstacles such as poor charge transfer in the electrode slurry and agglomeration of the electrode particles. Therefore, various FCDI electrode materials have been studied to overcome these bottlenecks through various mechanisms. Herein, a mini‐review is conducted to summarize the relevant information and provide a comprehensive view of the progress in FCDI electrode materials. Flow‐electrode materials can be classified into three main groups: carbon materials, metal‐based materials, and carbon–metal composites. Carbon‐based capacitive materials with outstanding conductivities can facilitate charge transfer in FCDI, whereas metal‐based materials and carbon–metal composites with ion‐intercalative behaviors exhibit high ion adsorption abilities. Additionally, carbon materials with surface function groups can enhance electrode dispersion and reach a high electrode loading by electrostatic repulsion, further upgrading the conductive network of FCDI. Moreover, magnetic carbon–metal composites can be easily separated, and the salt removal performance can be improved with magnetic fields. Different electrode materials exhibit disparate features during FCDI development. Thus, combining these materials to obtain FCDI electrodes with multiple functions may be reasonable, which could be a promising direction for FCDI research.