칼슘 코발트 층상 산화물계 열전반도체의 제조와 물성
Processing and Properties of Calcium CobaltiteLayer Structure Oxide Thermoelectrics
0
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
칼슘 코발트 층상 산화물계에서 Ca3Co2O6와 Ca3Co4O9를 기본으로 하여 열전 특성 향상을 위 해Ca 위치를 Bi, Sr, La, K로 부분 치환하고, Co위치를 Mn, Fe, Ni, Cu, Zn로 치환한 다결정 산화물을 제조하여 300∼1000K 까지의 열전 특성을 분석하였다. Bi가 치환된 Ca3Co4O9계의Ca2.7Bi0.3Co4O9는 전 기전도도 85.4(Ωcm)-1, Seebeck계수 176.2μV/K 그리고 파워팩터 265.2 μW/K2m로 가장 높은 열전 물성 치가 관찰되었다. 열전 모듈 제조를 위해서 각각의 열전반도체의 성능지수Z(10-4/K)가 0.87, 0.41의 값인 p형 열전 소재로 Ca2.7Bi0.3Co4O9를, n형 열전 소재로(Zn0.98Al0.02)O를 선택하여 열전쌍을 제조하였다. 제 조된 2쌍의 기본 열전쌍은 120K의 온도차에서 약30mV정도의 기전력이 나타났다.
Abstract
Thermoelectric properties of calcium cobalt layer structure oxide system, Ca3Co2O6 and Ca3Co4O9 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 Ca3Co4O9; Ca2.7Bi0.3Co4O9 for electrical conductivity, Seebeck coefficient and power factor were 85.4(cm)-1, 176.2V/K and 265.2W/K2m, respectively. The unit thermoelectric couple was fabricated with the p-type of Ca2.7Bi0.3Co4O9 and n-type (Zn0.98Al0.02)O thermoelectrics whose figure-of-merit(Z) were 0.8710-4/K and 0.4110-4/K, respectively. The generated thermoelectric power was about 30mV at the temperature difference of 120K in the unit thermoelectric couple.
참고문헌 (14)
- Y. Miyazaki, "Crystal structure and thermoelectric properties of the misfit-layered cobalt oxides", Solid State Ion, 172, pp.463~467 (2004)
- T. Takeuchi, "Electronic structure near the Fermi level in the Ca3Co4O9 layered cobalt oxide", J. Electron Spectrosc. Relat. Phenom, 144, pp.849~852 (2005)
- G. Xu, "High temperature transport properties of Ca3-xNax Co4O9 system", Solid State Commun, 124, pp.73~76 (2002)
- S. Li, "Synthesis and thermoelectric properties of the new oxide ceramics Ca3-xSrxCo4O9+δ (x=0.0-1.0)", Ceram. Inter, 27, pp.321~324 (2001)
- X. Luo, "Intergrowth and thermoelectric properties in the Bi-Ca-Co-O system", J. Cryst. Growth, 308, pp.309~313 (2007)
- S. Li, "Thermoelectric properties of oxides Ca2Co2O5 with Bi substitution", J. Mater. Sci, 19, pp.1339~1341 (2000)
- M. Mikami, "The effect of element substitution on high temperature thermoelectric properties of Ca3Co2O6 compounds", J. Solid State Chem, 178, pp.1670~1674 (2005)
- E. Guilmeau, "Neutron diffraction texture analysis and thermoelectric properties of BiCaCoO misfit compounds", Mater. Res. Bull (2007)
- C. Ling, "Structural investigation of oxygen non-stoichiometry and cation doping in misfit-layered thermoelectric (Ca2CoO3-x) (CoO)δ, δ≈1.61", J. Solid State Chem, 180, pp.1446~1455 (2007)
- J. Noudem, "Thermoelectric ceramics for generators", J. Eur. Ceram. Soc, 28, pp.41~48 (2008)
- M. Ohtaki, "Hightemperature thermoelectric properties of (Zn1-xAlx) O", J. Appl. Phys, 79, pp.1816~ (1996)
- S. Li, "Synthesis and thermoelectric properties of the new oxide materials Ca3-xBixCo4O9+δ (0.0<x<0.75)", Chem. Mater, 12, pp.2424~2427 (2000)
- Y. Masuda, "Thermoelectric performance of Biand Na-substituted Ca3Co4O9 improved through ceramic texturing", J. Mater. Chem, 13, pp.1094~1099 (2003)
- , 2007