Tungsten disulfide-reduced GO/CNT aerogel: a tuned interlayer spacing anode for efficient water desalination

Abstract

Owing to the favorable energy efficiency and environmental compatibility, capacitive deionization (CDI) has been greatly developed as a potential technology to overcome the ever-growing global water shortage. Herein, an effective and simple strategy is reported to boost the desalination performance by 30 percentage through expansion of interlayer spacing. The final redox active Hybrid CDI consists of WS2 nanoflowers embedded in a highly conductive free-standing rGO-CNT (WS2/rGO-CNT) aerogel as an anode and rGO-CNT aerogel as a cathode. WS2 is applied as a redox-active material for sodium ions intercalation, and three-dimensional (3D) rGO-CNT facilitates the diffusion of the ions to boost the reaction kinetics. Upon charging/discharging, sodium ions intercalate/deintercalate into/from the WS2 lattice structure which is confirmed via in-situ XRD measurements, and chloride ions are physically adsorbed/desorbed by rGO-CNT aerogel. Benefiting from the synergistic effect between highly conductive and porous rGO-CNT framework and WS2 nanoflowers with tuned structure, the as-assembled HCDI device enables stable desalination performance with superior removal capacity of 80 mg/g, and excellent removal rate of 3.9 mg/g/min.