Facial synthesis of FeOOH array-anchored carbon fiber as flow-through chloride-capturing electrode for ultrafast and super-stable capacitive deionization

Abstract

Faradic-based capacitive deionization (FDI) has been recognized as one of the most promising technologies to solve the freshwater crisis, yet was plagued by two most serious issues, i.e., slow desalination kinetics and poor cyclic stability. Herein, an ultrafast and super-stable FDI system is successfully developed based on the employment of a pseudocapacitive material as flow-through chloride-capturing electrode. While the pseudocapacitive material, anchoring FeOOH arrays on the surface of commercial carbon fiber cloth (CF@FeOOH) ensures high desalination durability by preventing possible FeOOH aggregation through the carbon fiber framework, the unique flow-through electrode enables fast mass transfer by channeling the feed stream inside its microchannels. Consequently, the FDI system equipped with flow-through CF@FeOOH electrodes displays an excellent desalination rate of 0.48 mg g−1 s−1 with ultra-robust cyclic stability (no reduction after 60 cycles and only 14.9 % capacity reduction after 150 cycles), while maintaining its high desalination capacity of 52.04 mg g−1, exemplifying the critical importance of both delicate material design and rational cell architecture.