Location：SKLC conference room
Time：2014.3.7 (Friday) 9:00 a.m.
Lecturer：Prof. Armin Feldhoff
Leibniz University Hannover, Institute of Physical Chemistry and Electrochemistry, Callinstrasse 3A, 30167 Hannover, Germany
Introduction：
Armin Feldhoff has been a Professor at the Faculty of Natural Sciences of the Leibniz Universit？t Hannover since 2012. He has been the Head of electron microscopy laboratory at the Institute of Physical Chemistry and Electrochemistry of the Leibniz Universit？t Hannover since 2003. He received his PhD from the Martin-Luther University of Halle-Wittenberg (summa cum laude) in 1997. He was a scientific co-worker at the Max-Planck Institute of Microstructure Physics in Halle from 1994-2001. After that, he spent a year as a postdoctoral associate at the Department of Materials Science and Engineering at Cornell University in 2001, and two years as a postdoctoral researcher at the Centre d’études de Chimie Métallurgique of the CNRS in Vitry sur Seine from 2001 to 2003. His current research interests include analytical high-resolution electron microscopy (HRTEM, EFTEM, STEM-HAADF, EELS, EDXS, SAED, CBED, FE-SEM) and X-ray diffractometry (XRD) and their application to problems in chemistry and materials sciences, and microstructure and functional properties of mixed ion and electron conducting oxides and of thermoelectric oxides.
Abstract：
Thermoelectric energy harvesting uses entropy current to drive an electrical current. Depending on the sign of the Seebeck coefficient α of the material, both currents are parallel or anti-parallel. The serial connection of n-type (α < 0) and p-type (α > 0) semiconducting legs with their contacts being alternatingly hot and cold, allows constructing thermoelectric modules, which can make use of the entropy current running from “hot” to “cold” for energy harvesting. Efficiency of these modules depends on three material parameters, which are Seebeck coefficient α = α(T), electrical conductivity s = s(T) and entropy conductivity L =L(T). A material is attractive for applications, if the dimensionless figure of merit zT = s ·α2/L is close to unity. Established materials, however, suffer from easy oxidation at high temperature, which makes them unsuitable for these conditions. If thermodynamic stability at high temperature counts, oxides are the materials of choice [1]. Starting from basic description of the principle, an overview about the actual situation is given. The lecture also describes the making of an oxide-based thermoelectric energy harvester and its performance in the high-temperature range [2].
Reference
[1] W. Zhou, J. Sunarso, M. Zhao, F. Liang, T. Klande, and A. Feldhoff, Angew. Chem. Int. Ed. 52 (2013) 14036.
[2] A. Feldhoff, B. Geppert, Energy Harvest. Systems (submitted)
Contacts：Group 504 Weiping Wang（9301）、Yanshuo Li（9137）