A High-Temperature Thermoelectric Generator Based on Oxides

verfasst von

Armin Feldhoff, Benjamin Geppert

Abstract

The thermoelectric energy conversion is described in terms of fluxes of extensive variables entropy and charge, which gives a clear meaning to the figure of merit and to the power factor. Strength and sign of coupling of entropy current and electrical current is decisive for the function of a thermoelectric generator, which was built from n-type and p-type oxide ceramics to be suitable for the high-temperature range. For n-type and p-type legs, Zn0.98Al0.02O and Ca3Co4O9-derived ceramics, respectively, were used. Microstructure of both materials was investigated to some detail by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy including elemental analysis. N-type Zn0.98Al0.02O shows sub-micrometre precipitates of ZnAl2O4 spinel. P-type Ca3Co4O9-derived ceramic is a multi-phase composite as the starting powder decomposed partly during sintering. The thermoelectric materials show different temperature slopes of the power factor with the p-type material reaching 1.8 mW cm-1 K-2 at 1,000 K and the n-type reaching 1.6 mW cm-1 K-2 at 1,050 K. For the 10-leg thermoelectric generator, a figure of merit of zT = 0.10 was estimated at maximum electrical power output when the hot side was at 1,023 K, and a temperature difference of 200 K was applied.

Organisationseinheit(en)

Institut für Physikalische Chemie und Elektrochemie

Typ

Artikel

Journal

Energy Harvesting and Systems - Materials, Mechanisms, Circuits and Storage (Print)

Band

1

Seiten

69-78

Anzahl der Seiten

10

ISSN

2329-8774

Publikationsdatum

01.06.2014

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Erneuerbare Energien, Nachhaltigkeit und Umwelt, Energieanlagenbau und Kraftwerkstechnik, Elektrotechnik und Elektronik, Elektrochemie

Ziele für nachhaltige Entwicklung

SDG 7 – Erschwingliche und saubere Energie

Elektronische Version(en)

https://doi.org/10.1515/ehs-2014-0003 (Zugang: Offen)
https://doi.org/10.1515/ehs-2014-0016 (Zugang: Offen)
https://doi.org/10.1515/ehs-2014-0016 (Zugang: Offen)