Anion Exchange Membranes for water, CO2 and CO2 to formic acid Electrolysis

Dioxide Materials has developed anion exchange membranes that can be used in water, CO2 and CO2 to formic acid electrolysis.

You now have options for alkaline water electrolyzers with base metal catalysts that exceed the performance of previous alkaline water electrolyzers with precious metal catalysts. We have run alkaline water electrolyzers (1 M KOH, 60 C) at 1 A/cm2 for over a year by using Sustainion® Anion Exchange Membranes. This advance makes electrochemical water conversion to H2 economically viable for biofuel production as described in “Electrochemical generation of syngas from water and carbon dioxide at industrially important rates”.

The same membranes have also run in CO2 electrolyzers at 200 mA/cm2 (3.0v) at room temperature for 6 months with no obvious degradation.   

The Sustainion® 37 membrane and ionomer use tetramethyl imidazoles which enable the membrane to work in both a CO₂ and a water cell.  Our recent work with imidazolium based ionic polymers as featured in Kutz et al.  Energy Technology  highlights why the polymers are much easier to work with than ionic liquids.  They stay put so you do not need a supporting electrolyte.

Imidazolium based ionic polymers are new interesting materials that have hardly been explored. You may want to try them in your own work.  Ionomer solutions containing 5% of the polymer above with R=CH3 X=Cl are available at:  We also offer crosslinked membranes of the same materials on the website.

You may also be interested in the paper, “Electrochemical conversion of CO2 to formic acid utilizing Sustainion™ membranes “, where we describe a novel three compartment cell configuration with the capability of directly producing a pure formic acid. The electrochemical cell employs a Dioxide Materials Sustainion® anion exchange membrane and a nanoparticle Sn GDE cathode containing an imidazole ionomer, allowing for improved CO2 electrochemical reduction performance.

We hope you will purchase membranes or cells to try them yourself. Dioxide Materials has been developing electrochemical technology for CO2 and water electrolysis and have working lab prototypes (membranes ionomers, cathode and anode electrodes, and research grade cell hardware) that are available for researchers to purchase. Please contact with any questions.