TY - JOUR
T1 - High Indirect Energy Consumption in AEM-Based CO2Electrolyzers Demonstrates the Potential of Bipolar Membranes
AU - Blommaert, Marijn A.
AU - Subramanian, Siddhartha
AU - Yang, Kailun
AU - Smith, Wilson A.
AU - Vermaas, David A.
PY - 2021
Y1 - 2021
N2 - Typically, anion exchange membranes (AEMs) are used in CO2 electrolyzers, but those suffer from unwanted CO2 crossover, implying (indirect) energy consumption for generating an excess of CO2 feed and purification of the KOH anolyte. As an alternative, bipolar membranes (BPMs) have been suggested, which mitigate the reactant loss by dissociating water albeit requiring a higher cell voltage when operating at a near-neutral pH. Here, we assess the direct and indirect energy consumption required to produce CO in a membrane electrode assembly with BPMs or AEMs. More than 2/3 of the energy consumption for AEM-based cells concerns CO2 crossover and electrolyte refining. While the BPM-based cell had a high stability and almost no CO2 loss, the Faradaic efficiency to CO was low, making the energy requirement per mol of CO higher than for the AEM-based cell. Improving the cathode-BPM interface should be the future focus to make BPMs relevant to CO2 electrolyzers.
AB - Typically, anion exchange membranes (AEMs) are used in CO2 electrolyzers, but those suffer from unwanted CO2 crossover, implying (indirect) energy consumption for generating an excess of CO2 feed and purification of the KOH anolyte. As an alternative, bipolar membranes (BPMs) have been suggested, which mitigate the reactant loss by dissociating water albeit requiring a higher cell voltage when operating at a near-neutral pH. Here, we assess the direct and indirect energy consumption required to produce CO in a membrane electrode assembly with BPMs or AEMs. More than 2/3 of the energy consumption for AEM-based cells concerns CO2 crossover and electrolyte refining. While the BPM-based cell had a high stability and almost no CO2 loss, the Faradaic efficiency to CO was low, making the energy requirement per mol of CO higher than for the AEM-based cell. Improving the cathode-BPM interface should be the future focus to make BPMs relevant to CO2 electrolyzers.
KW - anion exchange membrane
KW - bipolar membrane
KW - COelectrolysis
KW - COutilization
KW - crossover
KW - membrane electrode assembly
UR - http://www.scopus.com/inward/record.url?scp=85121903627&partnerID=8YFLogxK
U2 - 10.1021/acsami.1c16513
DO - 10.1021/acsami.1c16513
M3 - Article
AN - SCOPUS:85121903627
SN - 1944-8244
VL - 14
SP - 557
EP - 563
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 1
ER -