Controlled synthesis of bismuth oxychloride-carbon nanofiber hybrid materials as highly efficient electrodes for rocking-chair capacitive deionization

Rocking-chair Capacitive Deionization (RCDI) is one of the most promising cell architectures for highly efficient capacitive deionization (CDI) to address the fresh-water shortage, and developing Cl⁻-removal electrode materials of RCDI toward highly-efficient desalination (with high capacity and rate) is of utmost urgency. Herein we report our design on high-performance Cl⁻-removal electrode material via controllable anchoring of bismuth oxychloride nanostructures (BiOCl; such as nanoplates, nanoflowers, and nanospheres) on electrospun carbon nanofibers (BiOCl-CNF) for RCDI. The BiOCl-CNF based RCDI system displays excellent Cl⁻ storage capacitance as well as freestanding characteristics, which enables it to be a perfect electrode candidate for RCDI. By properly tailoring the composition of the hybrid material, the BiOCl-CNF based RCDI displays outstanding desalination efficacy in terms of desalination capacity (124 mg∙g⁻¹), energy consumption (66.8 Wh∙m⁻³), and desalination rate (0.52 mg‧g⁻¹‧s⁻¹), which are far more superior than the existing systems from the literatures, exemplifying the critical importance of delicate design in the Cl⁻-removal electrode materials for improving the desalination performance.