Effects of Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf> dopant on microstructure and thermoelectric properties of Na<inf>x</inf>CoO<inf>2</inf> ceramics

• Main Authors: Suwapitcha Buntham, Sukanda Jiansirisomboon, Anucha Watcharapasorn
• Format: Journal
• Published: 2018
• Subjects: Agricultural and Biological Sciences
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84944769323&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/44082
• Institution: Chiang Mai University

Copyright © 2015 American Scientific PublishersAll rights reserved. Bi 0.5 Na 0.5 TiO 3 -doped Na x CoO 2 ceramics with varied doping concentration of 0, 0.01, 0.03, 0.05 and 0.07 mol fraction were prepared by conventional solid state reaction method. The firing condition used was 950 °C for 8 h. X-ray diffraction pattern results showed that all produced ceramics were single phase with a hexagonal structure. Due to the substitution of BNT inside Na x CoO 2 lattice, there was a slight shift of X-ray diffraction pattern to the left which indicated the lattice expansion. The scanning electron micrographs of ceramics indicated that small amount of BNT addition could eliminate pore and improved densification. A small amount of undissolved BNT was also present in Na x CoO 2 matrix and dispersed at grain boundaries causing a decrease in grain size of the ceramic. The electrical conductivity and Seebeck coefficient of ceramics showed that all samples possessed metallic conduction behavior. However, BNT addition caused a reduction of electrical conductivity, Seebeck coefficient and power factor of Na x CoO 2 ceramics.