(482a) A Unified Look at Uptake and Transport in Ion Exchange Materials for Rfbs

Ion exchange membranes are frequently used in redox flow batteries. However, there are few general guidelines on how to select membranes. Uptake and transport of ions and the factors underlying them are critical determinants of thebehavior of conducting membranes. Substantial work was carried out on issues such as partitioning of ions into membranes in the early studies of Nafion. The heavy focus on fuel cell applications narrowed the scope of many studies to an emphasis on proton conduction. However, with the increased emphasis on redox flow batteries and other, similar electrochemical devices, there is a need to build a stronger base of studies of ions other than protons or hydroxide in various membrane situations. Furthermore, the operating conditions of the RFB typically entails exposure of membranes to concentrated electrolytes. We will report recent studies of the uptake, conduction and transport of ions in various membranes that are exposed to both aqueous and non-aqueous environments. In this presentation, we will describe the separation of factors determining permeation through ion exchange membranes and the molecular basis of these parameters. By comparing these behaviors across different membrane types, we will begin to systematize our understanding of the interactions leading to observed phenomena. In addition, we will outline our recent work in developing a description of the factors influencing uptake of ins in to membranes.

Acknowledgements

I would like to gratefully acknowledge the current support of this work by the Office of Naval Research and the U.S. Department of Energy, Office of Electricity Delivery and Energy Reliability (Dr. Imre Gyuk).