LAUSR

The dependence of performance and stability of a zero-gap CO2 electrolyzer on the properties of the anion exchange membrane (AEM) is examined. This work compares the influence of the anolyte when using an Aemion® membrane and shows that when using 10 mM KHCO3, a CO2 electrolyzer using a next generation Aemion+® membrane can achieve lower cell voltages and longer lifetimes due to increased water permeation. The impact of lower permselectivity of Aemion+® on water transport is also discussed. Using Aemion+®, a cell voltage of 3.17 V at 200 mA cm-2 is achieved at room temperature, with a faradaic efficiency of >90%. Stable CO2 electrolysis at 100 mA cm-2 is demonstrated for 100 h, but with reduced lifetimes at 300 mA cm-2. However, the lifetime of the cell at high current densities is shown to be increased by improving water transport characteristics of the AEM and reducing dimensional swelling, as well as by improving cathode design to reduce localized dehydration of the membrane.