Effect of La3+ substitution on the structural and thermoelectric properties of Ca3-xLaxCo4O9+δ. Issue 11 (September 2019)

• Record Type: Journal Article
• Authors: Cha, J.S.; Kim, D.H.; Hong, H.Y.; Kim, G.H.; Park, K.
• Is Part Of: Journal of the European Ceramic Society. Volume 39:Issue 11(2019)
• Page Start: 3320
• Page End: 3326
• Publication Date: 2019-09
• Subjects: Sol–gel process -- Sintering -- Electrical conductivity -- Microstructure -- Thermoelectric properties; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2019.04.030
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: The thermoelectric properties of Ca3 Co4 O9 were optimized by the substitution of La 3+ for Ca 2+ in Ca3 Co4 O9 . The La 3+ substitution significantly enhanced the thermoelectric power factor and reduced the lattice thermal conductivity. The lattice thermal conductivities at 800 °C for x = 0 and 0.3 samples were 1.80 and 1.34 Wm −1 K −1, respectively. The reduced thermal conductivity was mainly attributed to mass and strain field fluctuations in the crystal lattice. Ca2.7 La0.3 Co4 O9+ δ showed the largest dimensionless figure-of-merit (0.282 at 800 °C) by combining high power factor and the lowest lattice thermal conductivity. This work demonstrates that the La 3+ substitution is a highly effective approach for improving high-temperature thermoelectric properties.