LAUSR

Water is vital to the transport of ion through anion exchange membranes (AEMs). However, excessive water causes a decline in stabilities of AEMs. To better understand the water effect on AEMs, two states of water, bulk-like water and non-bulk-like water, were identified quantitatively in perfluorinated anion exchange membrane with seven IEC values in the range of 0.9–1.89 mequiv·g–1. Water in the membranes goes through a redistribution process as IEC changes, where non-bulk-like water content increases almost linearly and steadily with IEC; instead, bulk-like water content increases nonlinearly and sharply with IEC. Bulk-like water has a significant effect on the dimensional stability of the AEMs. It is an advisible strategy to increase IEC value from 0.90 to 1.45 mequiv·g–1 to improve the ion conductivity as well as reasonable dimensional stability of the AEMs.