A Desalination Battery Combining Cu3[Fe(CN)6]2 as a Na-Storage Electrode and Bi as a Cl-Storage Electrode Enabling Membrane-Free Desalination

A desalination battery is an attractive route for seawater desalination because it couples ion removal with energy storage. In this work, we paired Cu3[Fe(CN)6]2·nH2O as the Na-storage electrode with Bi as the Cl-storage electrode to construct a novel desalination battery that enables membrane-free desalination. Most current desalination technologies, with the exception of thermal distillation, rely on the use of membranes. Eliminating the need for a membrane can significantly simplify the construction and maintenance of desalination systems. After carefully examining the sodiation/desodiation reactions and cycle performance of Cu3[Fe(CN)6]2·nH2O in both acidic and neutral saline solutions (0.6 M NaCl), we combined Cu3[Fe(CN)6]2·nH2O with Bi, which was previously identified as a promising Cl-storage electrode, to construct a Cu3[Fe(CN)6]2·nH2O/Bi desalination battery. The Cu3[Fe(CN)6]2·nH2O/Bi desalination battery generates an electrical energy output during desalination, which is equivalent to dischargin...