Title: Fabrication and thermoelectric properties of NaxCoO2 by polymerised complex method

Authors: Min-Wook Oh; Stanley Abbey; Su-Dong Park; Bong-Seo Kim; Bok-Ki Min; Hee-Woong Lee

Addresses: Department of Materials Science & Engineering, Hanbat National University, 125 Dongseodae-ro, Yuseong-gu, Daejeon 34158, South Korea ' Department of Materials Science & Engineering, Hanbat National University, 125 Dongseodae-ro, Yuseong-gu, Daejeon 34158, South Korea ' Thermoelectric Conversion Research Center, Korea Electrotechnology Research Institute, 12, Bulmosan-ro 10 beon-gil, Seongsan-gu, Changwon-si Gyeongsangnam-do 51543, South Korea ' Thermoelectric Conversion Research Center, Korea Electrotechnology Research Institute, 12, Bulmosan-ro 10 beon-gil, Seongsan-gu, Changwon-si Gyeongsangnam-do 51543, South Korea ' Thermoelectric Conversion Research Center, Korea Electrotechnology Research Institute, 12, Bulmosan-ro 10 beon-gil, Seongsan-gu, Changwon-si Gyeongsangnam-do 51543, South Korea ' Thermoelectric Conversion Research Center, Korea Electrotechnology Research Institute, 12, Bulmosan-ro 10 beon-gil, Seongsan-gu, Changwon-si Gyeongsangnam-do 51543, South Korea

Abstract: Determination of thermoelectric properties of NaxCoO2 (x = 0.5, 0.6, 0.7, 0.8, 0.85, and 0.9) fabricated by polymerised complex (PC) method has been investigated in the temperature range 300-773 K. The single phase of NaxCoO2 was identified in samples with higher Na concentration (x > 0.7), while the second phase of Co3O4 was detected in that of lower Na concentration. The data from the measurement of Seebeck coefficients of all the samples suggest that they are p-type, which means that the major carrier concentrations are holes. The lowest electrical resistivity was obtained from sample x = 0.8. A fine microstructure was observed and is due to the PC method of fabrication, leading to low thermal conductivity. The maximum dimensionless figure of merit (ZT) of 0.25 at 773 K was evident in sample x = 0.8, which was mainly due to its lower electrical resistivity.

Keywords: NaxCoO2; thermoelectric; polymerised complex; thermal conductivity; Seebeck coefficient.

DOI: 10.1504/IJNT.2018.096343

International Journal of Nanotechnology, 2018 Vol.15 No.6/7, pp.528 - 536

Received: 08 May 2021
Accepted: 12 May 2021

Published online: 21 Nov 2018 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article