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 percent through an expansion of interlayer spacing. The final redox active hybrid CDI material 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 ion 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 the rGO-CNT aerogel. Benefiting from the synergistic effect between the highly conductive and porous rGO-CNT framework and WS₂ nanoflowers with a tuned structure, the as-assembled HCDI device enables stable desalination performance with a superior removal capacity of 80 mg g⁻¹, and an excellent removal rate of 3.9 mg g⁻¹ min⁻¹.