Thermoelectric characterization of fine-grained Ti5O9 Magneli phase ceramics

TL;DR

This study investigates the thermoelectric properties of fine-grained Ti5O9 ceramics, revealing their electrical behavior and a ZT value of 0.3 at high temperature, indicating potential for thermoelectric applications.

Contribution

It provides the first detailed thermoelectric characterization of Ti5O9 Magneli phase ceramics with nanometer-scale grains.

Findings

Electrical conductivity follows a small-polaron model.

Seebeck coefficient explained by a temperature-dependent Heikes-Chaikin-Beni model.

ZT reaches 0.3 at 1076 K.

Abstract

Magneli phase Ti5O9 ceramics with 200-nm grain-size were fabricated by hot-pressing nanopowders of titanium and anatase TiO2 at 1223 K. The thermoelectric properties of these ceramics were investigated from room temperature to 1076 K. We show that the experimental variation of the electrical conductivity with temperature follows a small-polaron model and that the Seebeck coefficient can be explained by a temperature-dependent Heikes-Chaikin-Beni model. The thermoelectric figure-of-merit ZT of this nanoceramic material reaches 0.3 at 1076 K.