William E. Mustain, Professor, Department of Chemical Engineering; Associate Dean for Research, College of Engineering and Computing, University of South Carolina
"New Materials vs. Reaction Engineering in Electrochemical Systems: Understanding Performance and Durability in Anion Exchange Membrane Fuel Cells and Electrolyzers"
Abstract:
In recent years, the desire to design, create and/or discover advanced functional nanomaterials has changed the way that faculty members and graduate students approach engineering research. Though there are many technologies where these materials can (and likely will) make a significant impact, the truth is that in most disciplines, materials with highly complex structures remain on the fringes of the technology. In some cases, even when so-called “advanced” materials are discovered there are significant difficulties in transitioning them from ex-situ tests to the real reacting environment. Therefore, must be careful to understand that material chemistry and structure are only two variables in an extremely complex system and often times there are other fundamental (e.g. electronic mobility, thermodynamic barriers, diffusivity) and engineering (porosity, concentration, temperature) properties that drive behavior in such environments. Additionally, there are systems where materials are being sought without a clear understanding of what is truly limiting performance and durability goal or the properties that are required of a real engineered system to operate effectively.
This presentation will focus on anion exchange membrane fuel cells (AEMFCs) and electrolyzers (AEMELs). They are linked in both their use of an anion exchange membrane (AEMs) as a low-cost solid polymer electrolyte as well as their overall chemistry and mass transport. Because they are emerging technologies, they are good examples where the literature is littered with exotic materials that claim to improve activity and stability (presumed as performance and durability in real devices). This talk will highlight five years of work in AEMFCs where the performance and durability of AEMFCs were improved significantly without any new materials – just using traditional chemical engineering principles for reactor engineering. Only later – once device operation was well understood and controlled – were new materials helpful. The discussion will then move to our past four years of work with AEMELs, where some of the principles from AEMFCs were translatable, but some were not, again requiring our team to assess where new materials (some now commercially available) and/or new operating regimes were needed to drive reactor operation.
A combination of electrochemical data (voltammetry, polarization, chronopotentiometry) and high-end physical characterization (neutron imaging, x-ray computed tomography, scanning-tunneling electron microscopy, etc.) will be shown. These studies aim to highlight: i) the importance and limitation of materials as first solutions to device-level problems; ii) recoverable and unrecoverable degradation mechanisms; iii) the need for electrode engineering and optimization; iv) the balance and sometimes compromise between performance and durability; and v) the absolute necessity in understanding how a system operates before proposing new solutions.
For more information about this project and the rest of our group, please visit https://www.mustainlab.com
Bio:
William (Bill) Mustain is a Professor in the Department of Chemical Engineering and Associate Dean for Research in the College of Engineering and Computing at the University of South Carolina. Professor Mustain has worked in several areas related to electrochemical energy generation and storage, including: high capacity materials for Li-ion batteries, novel electrode structures for Li-S batteries, catalysts and supports for proton exchange membrane and anion exchange membrane fuel cells and electrolyzers, electrochemical synthesis of fuels, electrochemical control of biological systems, the purposeful use of carbonates in low temperature electrochemical systems, and the electrochemical capture and utilization of CO2. Professor Mustain has been the PI or Co-PI on $19 M of externally funded research projects. He has published over 140 peer reviewed articles (h-index of 51), three book chapters and several patent applications to date and has over 100 invited and conference talks. He has been the recipient of several awards including the U.S. Department of Energy Early Career Award, Connecticut Quality Improvement Platinum Award, Supramaniam Srinivasan Young Investigator Award (Awarded by the Energy Technology Division of the Electrochemical Society), UConn Chemical Engineering Faculty of the Year Award, USC Chemical Engineering Publication Award, USC CEC Research Achievement Award, Illinois Institute of Technology Young Alumnus Award, and Fulbright Scholar Fellowship.