Armin Feldhoff

Group Leader Institut für Physikalische Chemie und Elektrochemie der Leibniz Universität Hannover
Research topics: Energy harvesting, thermoelectric materials and generators, mixed ionic and electronic conductors, energy harvesting, material microstructure and functional properties 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
Talk Title: 
Triple-phase ceramic nanocomposite with enhanced thermoelectric power factor
Talk Abstract: 
"Sol-gel process was used to produce heavily doped misfit-layered cobaltate Ca3Co4O9 [1], which by subsequent heat treatment in suitable atmosphere self-assembled into 2D nanocomposite as confirmed by high-resolution transmission electron microscopy (HRTEM) [2,3]. Nanocomposite was preserved in sintered ceramic, which showed enhanced thermoelectric properties parallel to the cold-pressing direction as applied to the green body. This went along with the preferential alignment of multiphase misfit-layered oxide platelets as confirmed by scanning electron microscopy (SEM). By increases in both the isothermal electrical conductivity and the Seebeck coefficient, the power factor was enhanced to 6.5 µW cm-1 K-2 at 1073 K in air. References [1] M. Bittner, L. Helmich, F. Nietschke, B. Geppert, O. Oeckler, A. Feldhoff, J. Eur. Ceram. Soc., 37 (2017) 3909 [2] M. Bittner, A. Feldhoff, DE 10 2017 216 990.7, patent pending [3] M. Bittner, N. Kanas, F. Steinbach, D. Groeneveld, R. Hinterding, P. Wemhoff, K. Wiik, M.-A. Einarsrud, A. Feldhoff, J. Solid State Chem. (submitted)"