Thermoelectric performance of Nb-doped SrTiO3 enhanced by reduced graphene oxide and Sr deficiency cooperation
authors Okhay, O; Zlotnik, S; Xie, WJ; Orlinski, K; Gallo, MJH; Otero-Irurueta, G; Fernandes, AJS; Pawlak, DA; Weidenkaff, A; Tkach, A
nationality International
journal CARBON
keywords DIELECTRIC PERMITTIVITY; POWER; CERAMICS; TEMPERATURE; TRANSPORT; VACANCIES; FIGURE; CARBON
abstract Oxide materials are of current interest as high-temperature thermoelectrics in the automotive and manufacturing energy-harvesting sectors due to high chemical robustness, low toxicity and low cost. Driven by a need to improve the thermoelectric performance of n-type oxides to the level of p-type analogues, ceramics and composites based on donor-doped SrTiO3 are considered as a promising material. Here Nb-doped SrTiO3 with Nb content of 10 and 15% as well as Sr/(Nb + Ti) ratio of 1.00 and 0.98 was mixed with 0.6 wt. % of graphene oxide (GO) prepared by Hummer-based method and conventionally sintered in atmosphere of H-2/N-2 to reduce both Nb-doped SrTiO3 and GO. Addition of reduced GO in combination with introduction of Sr vacancies provides a synergistic effect of fastening charge transport and thereby increasing electrical conductivity sigma and suppressing the thermal conductivity kappa. These factors, together with a moderate Seebeck coefficient S, result in a high power factor PF = S-2 x sigma up to similar to 1.98 mW/(K(2)m) and thermoelectric figure of merit ZT = PF x T/kappa up to 0.29. These findings offer further prospects for seeking high performance SrTiO3-based thermoelectrics by modification with reduced GO. (C) 2018 Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn 0008-6223
year published 2019
volume 143
beginning page 215
ending page 222
digital object identifier (doi) 10.1016/j.carbon.2018.11.023
web of science category Chemistry, Physical; Materials Science, Multidisciplinary
subject category Chemistry; Materials Science
unique article identifier WOS:000456710500024
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journal analysis (jcr 2017):
journal impact factor 7.082
5 year journal impact factor 7.088
category normalized journal impact factor percentile 86.140
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