(Lecture, MAR 20) Thermo-iono-electronic materials: Functional oxides in gas separation and energy harvesting
time: 2019-03-20

Title: Thermo-iono-electronic materials: Functional oxides in gas separation and energy harvesting
Speaker: Prof. Feldhoff (Leibniz Universität Hannover, Germany)
Time: 15:00p.m., March 20th, 2019
Venue: Room 405, Shaw Engineering Building, Wushan Campus

It is proposed to look at energy conversion from the point of view of thermo-ionic-electronic (TIE) materials or systems. In addition to ionic and/or electric charge carriers, entropy is considered as further basic quantity being transported through the material or system if the TIE is simultaneously placed in gradients of temperature and electrochemical potential (ionic and/or electronic). In the basic transport equation, the TIE appears as tensor, which is a major advantage over the concept of the so-called thermodynamics of irreversible processes. The role of energy and its conversion is easily understood by the flux of entropy, ionic charge carriers, and electronic charge carriers at their respective local potentials, which are the temperature, the ionic electrochemical potential, and the electronic electrochemical potential. Conversion of energy is easily understood as the loading of energy from entropy current (thermal energy = heat) to ionic current or electronic current (both electrochemical energy) or vice versa. Analogies between the Soret coefficient (thermo-ionic), the Seebeck coefficient (thermo-electric) and the ionic transfer number (ionic-electronic) become evident. The latter plays an important role in the context of the mixed ionic-electronic conductors (MIECs), which can be considered as TIEs under isothermal conditions and are of potential use in gas separation membranes. Also the thermoelectric (TE) coupling is considered to some detail with a focus on energy harvesting. Lecture will provide a theoretical framework and exemplary experimental results in both fields, energy harvesting as well as gas separation.
Prof. Feldhoff is engaged in the Physical Chemistry of Materials, and his research interests are in thermo-iono-electric (TIE) materials for energy conversion and gas separation. His activities link materials synthesis with the microstructure, as obtained by scanning and transmission electron microscopy as well as x-ray diffraction, and functionality. Aim is always a knowledge-based approach to bring new functionality into materials and devices. He has published more than 150 papers in peer-reviewed journals. Actually, his h-index is 42 with more than 6,000 citations. He received his diploma in physics from the University of Münster (Germany) and received his PhD degree from the Martin-Luther University Halle-Wittenberg (Germany). He was pre- and post-doctoral researcher at the Max Planck Institute of Microstructure Physics in Halle (Germany). He was postdoctoral associate at the Department of Materials Science and Engineering at Cornell University in Ithaca (NY, USA) and at the Centre d’Études de Chimie Métallurgique of the CNRS in Vitry sur Seine (France). He is head of the Nanostructure Laboratory at the Institute of Physical Chemistry and Electrochemistry of the Leibniz Universität Hannover (Germany) and holds the venia legendi for Physical Chemistry. In the German Society for Electron Microscopy, he is serving in the editorial team of Electron Microscopy. He is acting as associate editor of both Energy Harvesting & Systems and the Journal of Electronic Materials.