Event
ENERGY MATTERS SEMINAR: On Non-equilibrium Thermodynamics in Electrochemical Systems
Monday, May 13, 2024
1:00 p.m.-2:00 p.m.
1202 Engineering Lab Building
Catherine Stephens
301 405 9378
csteph5@umd.edu
http://energy.umd.edu
Xiao-Dong Zhou
Center for Clean Energy Engineering
Chemical and Biomolecular Engineering, Mechanical Engineering, and Materials Science and Engineering Departments, University of Connecticut, Storrs, CT 06269
Much of our understanding of physical behavior of materials is based on the concept of equilibrium, which lies at the heart of classical thermodynamics, condensed matter physics, and modern reaction kinetics. If a thermodynamic system is in equilibrium conditions, which is the situation when an energy system (e.g., a fuel cell or a battery) is under open circuit voltage, the surface and bulk of the electrode are only subject to fluctuation of thermodynamic qualities (e.g., temperature: T, pressure: P, molar number: n, and the chemical potential: μ). For the cases that are not at equilibrium, but are close to it, Onsager established linear reciprocal relationships between flux and thermodynamic force for a thermodynamic system in nonequilibrium states. These linear relationships are manifested in transport phenomena, which are non-equilibrium processes, such as ion diffusion and heat conduction.
If an electrochemical reaction takes place at an electrode of a fuel cell, electrolyzer, or battery, the thermodynamic system is far away from equilibrium. Therefore, the thermodynamic states of the surface and bulk of an electrode are subject to external thermodynamic forces (e.g., DT, Dn or Dμ). As a result, in an active electrode, the electrochemical reaction on the surface causes all thermodynamic variables to change in both the surface and the bulk. In this seminar, I will address three questions related to materials in non-equilibrium thermodynamic states: (i) how do fast kinetics and high current in an operating electrochemical cell affect the thermodynamic states of its material constituents, (ii) whether or not the state of non-equilibrium can remain stable with constant flow of matter and energy, and (iii) what is the origin that governs activity and stability in solid oxide cells?
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Professor Xiao-Dong Zhou is the Connecticut Clean Energy Fund professor in Sustainable Energy, The Nicholas E. Madonna Chair in Sustainability, Director of the, Center for Clean Energy Engineering, and a Professor in Chemical and Biomolecular Engineering, Mechanical Engineering, and Materials Science and Engineering at University of Connecticut. He is a special advisor to UConn President Radenka Maric in Sustainability. Dr. Zhou received J. B. Wagner Jr. Young Investigator Award in 2007 from the Electrochemistry Society (ECS) - High Temperature Materials (HTM) Division. He is the recipient of 2011 US DOD – DARPA Young Faculty Award. He is a Fellow of the Electrochemical Society. His research interests span theoretical and experimental studies of materials and interfaces for energy systems, including batteries, fuel cells, and electrolyzers. |
