doi:10.1016/j.jeurceramsoc.2018.12.049engTorres, M.A.Costa, F.M.Flahaut, D.Touati, K.Rasekh, S.Ferreira, N.M.Allouche, J.Depriester, M.Madre, M.A.Kovalevsky, A.V.Diez, J.C.Sotelo, A.Significant enhancement of the thermoelectric performance in Ca3Co4O9 thermoelectric materials through combined strontium substitution and hot-pressing processART-2019-109572This work explores the possibilities for a further enhancement of the thermoelectric properties of Ca3Co4O9 by Sr-doping combined with hot-pressing. Modified hot-pressing process resulted in highly-textured and dense ceramics. Sr-doping significantly improves electrical properties, resulting in extremely large power factor (1.2 mW/K2m at 800 °C) due to simultaneous electrical resistivity decrease and Seebeck coefficient increase. The main effect on cumulative electrical performance is provided by the Seebeck coefficient, reaching 270µV/K at 800 °C. XPS revealed relatively high average cobalt oxidation state at room temperature (+3.3), compared to materials produced by conventional sintering. The results of combined XPS and Auger electron spectroscopy emphasize the importance of high densification in Ca3Co4O9-based ceramics for preventing phase decomposition and interaction with CO2 and moisture. Still, despite the exceptional electrical performance, the calculated figure-of-merit (estimated as 0.29 at 800 °C) is around the best reported in the literature due to a high thermal conductivity (4.4 W/K m at room temperature).2019http://zaguan.unizar.es/record/8642410.1016/j.jeurceramsoc.2018.12.049http://zaguan.unizar.es/record/86424oai:zaguan.unizar.es:86424info:eu-repo/grantAgreement/ES/DGA/T54-17Rinfo:eu-repo/grantAgreement/ES/MINECO-FEDER/MAT2017-82183-C3-1-RJournal of the European Ceramic Society 39, 4 (2019), 1186-1192by-nc-ndhttps://creativecommons.org/licenses/by-nc-nd/4.0/deed.esinfo:eu-repo/semantics/openAccess