Membrane Engineering Reveals Descriptors of CO<sub>2</sub> Electroreduction in an Electrolyzer
Seok Hwan Yang, Wonsang Jung, H. Lee, Sang-Hun Shin, Seung Jae Lee, Min Suc, Woong Choi, Seong‐Geun Oh, Ki Bong Lee, Ung Lee, Da Hye Won, Jang Yong Lee
Abstract
Anion exchange membranes (AEMs) and ionomers are keys for electrochemical CO 2 reduction (eCO 2 R), but their development and multiple roles have not been intensively investigated. This study demonstrates HQPC-tmIM, a polycarbazole-based anion-conducting material, as a commercially viable AEM and reveals through multiphysics model simulation key descriptors governing eCO 2 R by exploiting the extraordinary membrane properties of HQPC-tmIM. The mechanical/chemical stability of HQPC-tmIM showed superior eCO 2 R performance in a membrane electrode assembly electrolyzer (MEA) in comparison to a commercial AEM (Sustainion). The CO partial current density ( j CO ) of −603 mA cm –2 on HQPC-tmIM MEA is more than twice that of Sustainion MEA and is achieved by only introducing HQPC-tmIM AEM and binder. The mutiphysics model revealed that the well-constructed membrane morphology of HQPC-tmIM leads to the outstanding membrane conductivity, and it enables high j CO through the facilitated charge transfer in overall reactions. This research suggests guidelines for developing a commercially viable AEM and ionomer for eCO 2 R.