Iryna V. Zenyuk

Professor

Department of Mechanical Engineering, Tufts University

Understanding Water Management in Fuel Cells through in-operando X-ray Computed Tomography

Understanding water transport in thin porous carbon materials is essential for water purification and energy applications. However, tools that are designed for characterizing porous media of a large scale (i.e. rocks, soils) are not always applicable for ultra-thin (< 500 um) layers. Synchrotron X-ray computed tomography (CT) is a fast, non-intrusive technique that allows quantification of morphological properties within porous media. For polymer-electrolyte fuel cells (PEFCs) and anion exchange membrane fuel cells (AEMFCs), effective water management is critical, especially at lower operating temperatures. Using synchrotron X-ray computed tomography (CT) we have shown previously the dependency of water transport properties on porous materials morphology and chemical composition, as well as cell compression. In our current work, in-operando fuel cell testing using synchrotron X-ray CT is used to observe steady-state water generation and removal in PEFCs and AEMFCs at temperatures of 30^oC and current densities of 20 – 100 mA/cm². Furthermore, comparison of water distribution in platinum group metals (PGM) and PGM-free catalysts for both types of fuel-cells will be presented. In all of these systems, water pooling was observed at the component interfaces, where larger voids were present due to specifics of fabrication methods. In parallel, we have developed multiphysics models to support the experimental efforts. With nano X-ray CT (60 nm resolution), it was possible to in-situ visualize three-dimensional water distribution in nano-porous carbon, enabling control of transport via material design.

Biography:

Professor Iryna Zenyuk received her Ph.D. (2013) from Carnegie Mellon University. Her graduate work focused on fundamental understanding of meso-scale interfacial transport phenomena and electric double layers in electrochemical energy-conversion systems. After a postdoctoral fellowship at Lawrence Berkeley National Laboratory in the Electrochemical Technologies Group, she joined the faculty of the Mechanical Engineering Department at Tufts University in 2015. At Tufts, Prof. Zenyuk is the director of SEELab (Sustainable Electrochemical Energy Lab). Her group works on high power-density, low-temperature hydrogen fuel-cells with a focus on addressing the problems of existing state-of-the-art fuel cells through a design strategy encompassing novel materials, chemistries, diagnostic tools and device-level testing.