Carbonaceous C@FeS Flow Electrode for Electrochemcal Capacitive Deionization Application

FeS has attracted much attention in the field of capacitive deionisation of flow electrodes due to its high theoretical specific capacity and wide range of sources. However, it usually exhibits frustrating performance due to its inherent low conductivity and volume expansion during charging and discharging. Herein, we successfully prepared calcium alginate-coated FeS carbon spheres (C@FeS) with a hollow nanosphere structure by a combination of sol-gel and solid-phase sintering using sodium alginate as a carbon source. This unique hollow structure provides enough space for the expansion of FeS and enhances the stability of the sulfide; meanwhile, the internal “surface-line-surface” structure not only facilitates the migration and charge transfer of ions inside, but also provides more active electrosorption sites. When assembled as the flow electrode of the flow electrode capacitive deionisation (FCDI) system, the desalination capacity of the electrode was improved from 25.32 mg g −1 to 53.12 mg g −1 . Therefore, the C@FeS composite is expected to provide a new candidate electrode material for the FCDI system, which will make the future desalination process more cost-effective and efficient.