(545an) Silver/Silver Chloride Electrodes for Deionization

The ability of silver electrodes to sequester chloride during oxidation has been applied in various water purification systems such as desalination batteries. This electrode exhibits a number of useful characteristics including excellent cyclability, which is essential in such applications. Here we analyze in detail the mechanisms controlling energy loss associated with chloride removal by Ag/AgCl electrodes in desalination applications and their subsequent regeneration. Contributions include ohmic losses in bulk solution near the electrode and through the porous AgCl overlayer as well as losses corresponding to concentration polarization and activation overpotential. We briefly review literature on desalination applications of Ag/AgCl electrodes and measurements of the fundamental electrochemical properties of this system. We then apply these parameters to model desalination systems using Ag/AgCl electrodes and compare these to measurements using porous silver electrodes. These analyses point to the practical energy efficiencies which are achievable using Ag/AgCl electrodes for desalination.