Wang Weitian, Ding Lei, Xie Zhiqiang, Yu Shule, Canfield Brian, Bender Guido, Wrubel Jacob A, Pivovar Bryan S, Zhang Feng-Yuan
Department of Mechanical, Aerospace & Biomedical Engineering, UT Space Institute, University of Tennessee, Knoxville, Tullahoma, TN, 37388, USA.
Chemistry & Nanoscience Department, National Renewable Energy Lab, Golden, CO, 80401, USA.
Small. 2023 Jul;19(28):e2207809. doi: 10.1002/smll.202207809. Epub 2023 Apr 7.
In situ and micro-scale visualization of electrochemical reactions and multiphase transports on the interface of porous transport electrode (PTE) materials and solid polymer electrolyte (SPE) has been one of the greatest challenges for electrochemical energy conversion devices, such as proton exchange membrane electrolyzer cells (PEMECs), CO reduction electrolyzers, PEM fuel cells, etc. Here, an interface-visible characterization cell (IV-CC) is developed to in situ visualize micro-scaled and rapid electrochemical reactions and transports in PTE/SPE interfaces. Taking the PEMEC of a green hydrogen generator as a study case, the unanticipated local gas blockage, micro water droplets, and their evolution processes are successfully visualized on PTE/PEM interfaces in a practical PEMEC device, indicating the existence of unconventional reactant supply pathways in PEMs. Further comprehensive results reveal that PEM water supplies to reaction interfaces are significantly impacted with current densities. These results provide critical insights about the reaction interface optimization and mass transport enhancement in various electrochemical energy conversion devices.
在多孔传输电极（PTE）材料与固体聚合物电解质（SPE）界面上进行电化学反应和多相传输的原位及微观尺度可视化，一直是电化学能量转换装置面临的最大挑战之一，这些装置包括质子交换膜电解槽（PEMEC）、CO还原电解槽、PEM燃料电池等。在此，开发了一种界面可视表征池（IV-CC），用于原位可视化PTE/SPE界面上微观尺度的快速电化学反应和传输。以绿色氢气发生器的PEMEC为例，在实际的PEMEC装置中，成功地在PTE/PEM界面上可视化了意外的局部气体堵塞、微小水滴及其演变过程，这表明PEM中存在非常规的反应物供应途径。进一步的综合结果表明，PEM向反应界面的水供应受到电流密度的显著影响。这些结果为各种电化学能量转换装置中的反应界面优化和传质增强提供了关键见解。
