Processing and Properties of Calcium Cobaltite Layer Structure Oxide Thermoelectrics

칼슘 코발트 층상 산화물계 열전반도체의 제조와 물성

  • Kwak, Dong-Ha (Division of Energy Systems Research, Graduate school, Ajou University) ;
  • Park, Jong-Won (Department of Materials Science and Engineering, Ajou University) ;
  • Yoon, Sun-Ho (Division of Energy Systems Research, Graduate school, Ajou University) ;
  • Choi, Jung-Chul (Department of Materials Science and Engineering, Ajou University) ;
  • Choi, Seung-Chul (Division of Energy Systems Research, Graduate school, Ajou University)
  • 곽동하 (아주대학교 에너지시스템공학부) ;
  • 박종원 (아주대학교 재료공학과) ;
  • 윤선호 (아주대학교 에너지시스템공학부) ;
  • 최정철 (아주대학교 재료공학과) ;
  • 최승철 (아주대학교 에너지시스템공학부)
  • Published : 2008.03.30

Abstract

Thermoelectric properties of calcium cobalt layer structure oxide system, $Ca_3Co_2O_6$ and $Ca_3Co_4O_9$ were investigated at the temperature range of 300 to 1000K for the application of thermoelectric generation. In the composition, the Ca site was partially substituted with Bi, Sr, La, K and the Co site was partially substituted with Mn, Fe, Ni, Cu, Zn. The thermoelectric properties of Bi substituted $Ca_3Co_4O_9$. $Ca_{2.7}Bi_{0.3}Co_4O_9$ for electrical conductivity, Seebeck coefficient and power factor were $85.4({\Omega}$cm)^{-l}, $176.2{\mu}V/K$ and $265.2{\mu}W/K^m$, respectively. The unit thermoelectric couple was fabricated with the p-type of $Ca_{2.7}Bi_{0.3}Co_4O_9$ and n-type ($Zn_{0.98}Al_{0.02}$)O thermoelectrics whose figure-of-merit(Z) were $0.87{\times}10^{-4}/K$ and $0.41{\times}10^4/K$, respectively. The generated thermoelectric power was about 30mV at the temperature difference of 120K in the unit thermoelectric couple.