Jakubczyk, E. M.Mapp, A.Chung, C. C.Sansom, Christopher L.Jones, J. L.Dorey, Robert A.2019-03-042019-03-042019-02-19E.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. 91-1010925-8388https://doi.org/10.1016/j.jallcom.2019.02.199https://dspace.lib.cranfield.ac.uk/handle/1826/13960High 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.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/CeramicsThermoelectric materialsOxide materialsSol-gel processingScanning electron microscopyArticle