Rocking Chair Desalination Battery Based on Prussian Blue Electrodes.

The demand for fresh water has been increasing, caused by the growing population and industrialization throughout the world. In this study, we report a capacitive-based desalination system using Prussian blue materials in a rocking chair desalination battery, which is composed of sodium nickel hexacyanoferrate (NaNiHCF) and sodium iron HCF (NaFeHCF) electrodes. In this system, ions are removed not only by charging steps but also by discharging steps, and it is possible to treat actual seawater with this system because the Prussian blue material has a high charge capacity with a reversible reaction of alkaline cations. Here, we demonstrate a rocking chair desalination battery to desalt seawater, and the results show that this system has a high desalination capacity (59.9 mg/g) with efficient energy consumption (0.34 Wh/L for 40% Na ion removal efficiency).