Overcoming voltage issue in bicarbonate electrolysis: Dual mass-transfer pathways for CO2 and ions
Sae In Suh, Youngrok Lee, Jae‐Young Choi, Hansung Kim, Hyung‐Suk Oh, Woong Hee Lee
Abstract
The direct electrolysis of CO 2 -captured liquid, such as bicarbonate, offers economic advantages by eliminating the CO 2 regeneration step. However, high cell voltages remain a major barrier. Herein, we propose a new strategy to build dual mass-transfer pathways for CO 2 and ions using a carbon and anion exchange ionomer (AEI) to reduce cell voltages while achieving sufficient Faradaic efficiency (FE) for the CO 2 reduction reaction. By optimizing the interposer materials and ratio of carbon, Ag, and AEI, sufficient FE CO (57%) and low cell voltages (3.17 V) were achieved at 100 mA cm −2 . The formation of dual mass-transfer pathways in bicarbonate electrolysis was confirmed through in situ/operando visualization studies. To ensure stability, we recommend the generation of dual mass-transfer pathways using chemically and physically stable materials. Our work provides an understanding of the mass transfer in bicarbonate electrolysis and a direction for overcoming the voltage issue.