Park, Hyungjoo Kwon, Giyun Lee, Hyomin Lee, Kyunam Park, Soo Young Kwon, Ji Eon Kang, Kisuk Kim, Sung Jae 2024-01-19T12:32:19Z 2024-01-19T12:32:19Z 2022-04-03 2022-03 0027-8424 https://pubs.kist.re.kr/handle/201004/115577 Redox flow batteries (RFBs) are attractive large-scale energy storage techniques, achieving remarkable progress in performance enhancement for the last decades. Nevertheless, an in-depth understanding of the reaction mechanism still remains challenging due to its unique operation mechanism, where electrochemistry and hydrodynamics simultaneously govern battery performance. Thus, to elucidate the precise reactions occurring in RFB systems, an appropriate analysis technique that enables the real-time observation of electrokinetic phenomena is indispensable. Herein, we report in operando visualization and analytical study of RFBs by employing a membrane-free microfluidic platform, that is, a membrane-free microfluidic RFB. Using this platform, the electrokinetic investigations were carried out for the 5,10-bis(2-methoxyethyl)-5,10-dihydrophenazine (BMEPZ) catholyte, which has been recently proposed as a high-performance multiredox organic molecule. Taking advantage of the inherent colorimetric property of BMEPZ, we unravel the intrinsic electrochemical properties in terms of charge and mass transfer kinetics during the multiredox reaction through in operando visualization, which enables theoretical study of physicochemical hydrodynamics in electrochemical systems. Based on insights on the electrokinetic limitations in RFBs, we verify the validity of electrode geometry design that can suppress the range of the depletion region, leading to enhanced cell performance. English National Academy of Sciences In operando visualization of redox flow battery in membrane-free microfluidic platform Article 10.1073/pnas.2114947119 1 Proceedings of the National Academy of Sciences of the United States of America, v.119, no.9 Proceedings of the National Academy of Sciences of the United States of America 119 9 Y scie scopus 000766704900005 2-s2.0-85125215184 Multidisciplinary Sciences Science & Technology - Other Topics Article FUEL-CELL X-RAY TRANSVERSE DIFFUSION MIXING REACTANTS PERFORMANCE ELECTRODES ENERGY CHANNEL membrane-free redox flow battery in operando visualization multiredox organic molecule in-depth study electrochemistry and hydrodynamics