Investigating transport of ethanol within hydrocarbon anion exchange membranes for CO2 electrolysis

A kilowatt-hour produced using renewable energy is rapidly becoming cheaper than equivalent fossil fuel energy production methods. Simultaneously, CO2 capture technologies are approaching commercialization and are projected to give industry access to a surplus of CO2. What should be done with abundant clean energy and CO2? CO2 electrolysis could be the answer; it is a promising technology that creates commodity chemicals like ethanol, methanol, ethylene, and formic acid from CO2. Several inefficiencies need to be addressed to advance the technology to commercial relevancy. Within alkaline CO2 electrolysers, newly formed products diffuse into and across the anion exchange membrane, which is shown to negatively effect the membrane. Five hydrocarbon membranes were compared giving insight into how effectively different membrane chemistries exclude ethanol. Diffusion-ordered spectroscopy and permeability tests were used for measuring the diffusion coefficients of ethanol within these membranes. Crosslinking and zwitterionic functional groups showed potential to abate ethanol diffusion.