Title: Carbon Dioxide and Water Electrolysis Using New Alkaline Stable Anion Membranes

Abstract

The recent development and market introduction of a new type of alkaline stable imidazole-based anion exchange membrane and related ionomers by Dioxide Materials is enabling the advancement of new and improved electrochemical processes which can operate at commercially viable operating voltages, current efficiencies, and current densities. These processes include the electrochemical conversion of CO₂ to formic acid (HCOOH), CO₂ to carbon monoxide (CO), and alkaline water electrolysis, generating hydrogen at high current densities at low voltages without the need for any precious metal electrocatalysts. The first process is the direct electrochemical generation of pure formic acid in a three-compartment cell configuration using the alkaline stable anion exchange membrane and a cation exchange membrane. The cell operates at a current density of 140 mA/cm² at a cell voltage of 3.5 V. The power consumption for production of formic acid (FA) is about 4.3–4.7 kWh/kg of FA. The second process is the electrochemical conversion of CO₂ to CO, a key focus product in the generation of renewable fuels and chemicals. The CO₂ cell consists of a two-compartment design utilizing the alkaline stable anion exchange membrane to separate the anode and cathode compartments. A nanoparticle IrO₂ catalyst on a GDE structure is usedmore » as the anode and a GDE utilizing a nanoparticle Ag/imidazolium-based ionomer catalyst combination is used as a cathode. The CO₂ cell has been operated at current densities of 200 to 600 mA/cm² at voltages of 3.0 to 3.2 respectively with CO₂ to CO conversion selectivities of 95–99%. The third process is an alkaline water electrolysis cell process, where the alkaline stable anion exchange membrane allows stable cell operation in 1 M KOH electrolyte solutions at current densities of 1 A/cm² at about 1.90 V. The cell has demonstrated operation for thousands of hours, showing a voltage increase in time of only 5 μV/h. The alkaline electrolysis technology does not require any precious metal catalysts as compared to polymer electrolyte membrane (PEM) design water electrolyzers. Here, we discuss the detailed technical aspects of these three technologies utilizing this unique anion exchange membrane.« less

Authors:

Kaczur, Jerry J.; Yang, Hongzhou; Liu, Zengcai; Sajjad, Syed D.; Masel, Richard I.

Publication Date:

Tue Jul 03 00:00:00 EDT 2018

Research Org.:

Dioxide Materials, Boca Raton, FL (United States); 3M Company, Maplewood, MN (United States)

Sponsoring Org.:

USDOE Advanced Research Projects Agency - Energy (ARPA-E)

Contributing Org.:

LanzaTech, Skokie, IL (United States)

OSTI Identifier:

1458782

Alternate Identifier(s):

OSTI ID: 1458767

Grant/Contract Number:  

SC0004453; AR0000684

Resource Type:

Published Article

Journal Name:

Frontiers in Chemistry

Additional Journal Information:

Journal Name: Frontiers in Chemistry Journal Volume: 6; Journal ID: ISSN 2296-2646

Publisher:

Frontiers Research Foundation

Country of Publication:

Switzerland

Language:

English

Subject:

08 HYDROGEN; 10 SYNTHETIC FUELS; 25 ENERGY STORAGE; Anion membranes; electrochemical; formic acid; carbon monoxide; CO2 utilization; alkaline water electrolysis