and their Sustainion © membrane which has shown 1000's of hours of stability, albeit under specific operating conditions. Without sufficient bicarbonate/carbonate transport through the membrane, the concentration of buffering ions will increase over time, forcing co-ion transport through the membrane and resulting in electrolyte precipitation, destroying the membrane and/or the gas-diffusion layer. Without solutions to these issues it will be difficult for either membrane electrode assemblies or alkaline catholytes to be paired with anion exchange membranes in a practical CO2 reduction device.