Improving the thermoelectric properties of SrTiO3-based ceramics with metallic inclusions

Deepanshu Srivastava (1) , Colin Norman (1) , Feridoon Azough (1) , Marion C. Schafer (2) , Emmanuel Guilmeau (2) , Robert Freer (1)

1 University of Manchester [Manchester]
2 CRISMAT - Laboratoire de cristallographie et sciences des matériaux

High quality Sr0.8La0.067Ti0.8Nb0.2O3-delta ceramics containing inclusions of Cu or Fe were prepared by the mixed oxide route and sintered under reducing conditions at 1700 K. Products were high density; Fe enhanced density (to 98% theoretical) and grain size (to 15 mm) whilst Cu tended to reduce both slightly. XRD and SEM analyses showed that the material is mainly composed of cubic SrTiO3 phase, with rutile-structured minor phases and metallic inclusions along the grain boundaries. The inclusions increased carrier concentration and carrier mobility, leading to a reduction in electrical resistivity by a factor of 5 and increase in power factor by 75%. Both types of metallic inclusions were beneficial, increasing the thermoelectric figure of merit (ZT) from 0.25 at 1000 K for the control sample, to ZT of 0.36 at 900 K for the Cu-containing samples and to 0.38 at 1000 K for the Fe-containing samples. (C) 2017 The Authors. Published by Elsevier B.V.

Keywords: Perovskite; Thermoelectric; Inclusions; Oxide; Grain boundary

Domains: Engineering Sciences [physics]; Materials

Deepanshu Srivastava, Colin Norman, Feridoon Azough, Marion C. Schafer, Emmanuel Guilmeau, et al.. Improving the thermoelectric properties of SrTiO3-based ceramics with metallic inclusions. Journal of Alloys and Compounds, 2018, 731, pp.723-730. ⟨10.1016/j.jallcom.2017.10.033⟩. ⟨hal-02174382⟩