If you enjoy reading “the numbers” and gathering data about CO2 recycling, you’ll want to take some time with a 2016 report entitled “Sustainion Imidazolium‐Functionalized Polymers for Carbon Dioxide Electrolysis”. Opening with a concise explanation of the need to find effective and large-scale methods of mitigating climate change, it goes on to an in-depth look at the cathode electrode membranes from Dioxide Materials as an ideal way to achieve that goal.
In the report, it explains that the “addition of an imidazolium group onto the styrene side‐chains increases the selectivity of the reaction from approximately 25 % to approximately 95 %. The current at 3 V is increased by a factor of 14…[and] cell potential with a CO product selectivity over 98 %.” The report also notes that this stable performance was sustained for more than six months, demonstrating that the imidazolium polymers on the cathode electrode are the ideal options for CO2 electrolysis or recycling.
And though this demonstrates that the Dioxide Materials’ membrane and cathode electrode is effective, it does not quite explain whether it is cost effective. Firstly, it is well-known that ionic liquids are both costly and corrosive. Finding an alternative that can be used on the commercial scale has been a priority for many groups, and for Dioxide Materials, their cathode electrode was one of the end results.
As explained by the firm, repeated trials and studies have shown that their Sustainion® Anion exchange membranes, which are imidazolium functionalized styrene polymer membranes offer superior conductivity and high current densities at low voltage. They are included in the electrolyzers which feature a zero gap are used in along with a compartmented cell design. Theis systemelectrolyzer cells features flowfields, anodes and cathodes,a GDE cathode electrode with nanoparticle tin electrocatalysts and Sustainion® ionomer, the Sustainion® Anion exchange membrane, center compartment with strong acid media, anode side cation membrane and various parts to complete a “plug and play” system.anode with IrO2 electrocatalyst.
This technologye design has raised the current and lifetime of the CO2 electrolyzer into a commercially useful range and shown high conductivities and selectivity.above 100 mS/cm under alkaline conditions at 60 °C. They have demonstrated a lifetime over 4000 hours in CO2 electrolyzers at high current densities and have stability for thousands of hours.. Adaptable to an array of industries, they stand alone as one of the premium options in the CO2 recycling process.
They have gone on to develop more enhancements and equipment, but the thrust of the work has been to enable scaling of the technologies to commercially feasible levels, ensuring a reduction in renewable energy curtailing, development of valuable feed stocks from CO2 supplies, and environmental improvements on a global scale.