Effects of structure and chemistry on electrochemical transport properties of anion exchange membranes for separation of CO2

The effects of structure, chemistry, and morphology of an anion exchange membrane (AEM) for separation of CO2 from a humidified gas mixture were characterized to determine the influence on the kinetics and transport properties of a membrane electrode assembly (MEA). Supported and unsupported membranes with thicknesses of 30 mu m and 50 mu m were used to determine through-plane resistance, ion transport capacity, and gas diffusion properties. The effects of membrane saturation on the membrane resistance was characterized by impedance measurements under conditions with varying relative humidity from 0% to 100%. Permeability measurements with varying CO2 concentration from 1% CO2 to 10% CO2 at temperatures of 25 degrees C and 35 degrees C determined changes in the membrane behavior, which could influence the performance of the CO2 separating MEA. This study characterized how AEM properties influence the behavior and performance of an electrochemical separating CO2 MEA suitable for high-humidity, low CO2 concentration environments. Pt and IrO2 electrodes were used evaluate the performance of unsupported and supported membranes within a MEA, characterized by electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and constant-current measurements to examine the CO2 electromigration.