Enhancing thermoelectric properties of NaCo2O4 ceramics through Na pre-treatment induced nano-decoration

Date published

2019-02-19

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Elsevier

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Article

ISSN

0925-8388

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Citation

E.M. Jakubczyk, A. Mapp, C.C. Chung, et al., (2019) Enhancing thermoelectric properties of NaCo2O4 ceramics through Na pre-treatment induced nano-decoration. Journal of Alloys and Compounds, Volume 788, June 2019, pp. 91-101

Abstract

High quality NaCo2O4 thermoelectrics are challenging to process due to the volatile nature of Na, the slow densification kinetics, and degradation of NaCo2O4 above 900–950 °C leading to the formation of Na-poor second phases. Fine grained sol-gel derived powders have been used to enhance the densification kinetics while pre-treatment of the NaCo2O4 powder with NaOH, to provide a Na rich environment, has been shown to mitigate Na loss at elevated temperatures. While insufficient to compensate for Na loss at processing temperatures of 1000 °C and above, at lower temperatures it is able to enhance densification and facilitate the formation of complex crystal structures yielding low thermal conductivity (0.66 Wm−1K−1) coupled with high electrical conductivity (3.8 × 103 Sm−1) and a Seebeck coefficient of 34.9. The resultant room temperature power factor and ZT were 6.19 × 10−6 Wm−1K−2 and 0.0026, respectively.

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Github

Keywords

Ceramics, Thermoelectric materials, Oxide materials, Sol-gel processing, Scanning electron microscopy

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Attribution 4.0 International

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