(482f) Neutron Imaging to Visualize Ion Transport in Electrochemical Cells

Understanding transport phenomena of ions in an electrochemical cell is important for the development and improvement of various water-treatment and energy-recovery processes including capacitive deionization for the desalination of saline water, electrochemical treatment of high-salinity wastewaters, energy storage in supercapacitors, and capacitive energy recovery of mixing seawater with fresh water, also known as blue energy. Real-time visualization of changes in the spatial distribution of ions in electrochemical cells can provide useful insights that can be used to further develop and improve these processes. An effort has recently been focused on real-time visualization of the spatial ion distribution using an in-situ neutron imaging technique. Compared to visualization techniques using other radiation sources, neutron imaging is a more promising option because it is noninvasive and nondestructive. This study is focused on reviewing theoretical and experimental investigations, including our own recent work, based on neutron imaging to visualize ion transport under various conditions. Basic principles of neutron imaging describing interactions of neutrons with matter will be briefly reviewed, and application examples will be discussed, including electrosorption of ions by mesoporous carbon electrodes for the desalination of saline water and blue energy generation. Comparisons of experimental observations with other experimental and modeling investigations, as well as limitations of the neutron imaging technique, will also be discussed.