High speed capacitive deionization system with flow-through electrodes

Capacitive deionization (CDI) is considered as a promising approach to sustain fresh water supply with environmental friendliness and convenient electrode regeneration. As a novel CDI system, flow-through electrode (FTE) CDI is drawing researchers' attention due to its structural simplicity, highly compact cells, cost effectiveness, and fast salt adsorption kinetics that are applicable for large-scale desalination of saline water. However, the FTE CDI architecture requires electrodes with robust structures and preferable permeability, considering the direct flow through mechanism, which limits their choices of electrode materials. Herein, we propose a facial electrospinning method to fabricate three-dimensional TiO₂ encapsulated carbon nanofiber (TiO₂@CNF), which possesses good mechanical stability and highly permeable macroporous-mesoporous structure to endure the reasonable feed pressure upon high-speed influent flushing. Moreover, the TiO₂@CNF electrode shows evident pseudo-capacitive performance as well as high electrical conductivity. By integrating the features of both the TiO₂@CNF and the FTE CDI architecture, the as-fabricated system displays a salt removal capacity of 15.50 mg g⁻¹ and a desalination rate of 1.26 mg g⁻¹ min⁻¹ at 1.4 V. The TiO₂@CNF provides a promising alternative for FTE CDI towards the future desalination technologies.