Flexible self-supporting CoFe-LDH/MXene film as a chloride ions storage electrode in capacitive deionization

Excessive chloride ions (Cl-) are undesirable in water. However, most of the research on the application of capacitive deionization in desalination has focused on cation storage electrode materials, whereas less on the equally important Cl- storage electrode materials. Herein, the CoFe-Layered Double Hydroxide (CoFe-LDH) prepared by chemical co-precipitation was composited with MXene through simple vacuum filtration to form a self-supporting CoFe-LDH/Ti3C2Tx film electrode, and used as the anode material to store Cl- in the hybrid capacitive deionization system. The CoFe-LDH/Ti3C2Tx composite film has a hierarchical micro-mesoporous architecture, larger electrochemical capacity, and desalination capacity, reaching 149.25 ± 6.17 mg g−1 at a current density of 50 mA g−1 and desalination rate of 3.86 mg g−1 min−1 at 100 mA g−1. This work provides potential inspiration for the Cl- storage electrode for capacitive deionization technology.