Integrating FeOOH with bacterial cellulose-derived 3D carbon nanofiber aerogels for fast and stable capacitive deionization based on accelerating chloride insertion

Faradic capacitive deionization (FDI), as an emerging research branch of capacitive deionization (CDI), has shown its great potential to relieve global water stress owing to its high desalination capacity/efficiency, flexible scale, and zero secondary pollution characteristics. However, the slow desalination kinetics and poor cyclic stability of the anion-capturing electrode of current FDI systems greatly limit its practical application. Herein, we proposed a strategy of interweaving FeOOH nanospindle inside the 3D network structure of carbon nanofiber aerogel to construct a 3D network structure (CNFAs@FeOOH) and further used it as a chloride capture electrode for FDI. As a result, the FDI system equipped with CNFAs@FeOOH enjoys excellent desalination performance with an ultrahigh desalination rate of up to 0.33 mg g−1 s−1. More importantly, the CNFAs@FeOOH-based FDI system enjoys excellent cycling stability with no significant decrease in 100 cycles and only 17.85 % decrease in 200 cycles. Carbon nanofiber aerogel interweaved FeOOH was introduced as chloride-insertion electrodes for faradic capacitive deionization, achieving durable and fast desalination. [Display omitted] •Carbon nanofiber aerogel interweaved FeOOH (CNFAs@FeOOH) was used as the anode of faradic capacitive deionization (FDI).•The 3D network structure of CNFAs@FeOOH prevents aggregation between FeOOH and enables rapid charge/electron transfer.•The open porous structure of CNFAs@FeOOH allows flow-through water mode to accelerate mass transfer.•The CNFAs@FeOOH-based FDI system displays an ultrahigh desalination rate with excellent long-term stability.