Sr掺杂对Ca_3Co_4O_9基材料热电性能的影响

Effects of Sr Doping on the Thermoelectric Properties of Ca_3Co_4O_9-based Materials

采用溶胶-凝胶法,结合常压烧结工艺制备了Ca3-xSrxCo4O9(x=0～0.5)热电陶瓷材料,并对材料的热电性能进行了测试。结果表明,Sr掺杂对Ca3Co4O9基材料的热电性能有较大影响。随着掺杂量的增加,电导率逐渐增大,Seebeck系数略有减小。Sr掺杂能显著降低热导率,而且随着掺杂量的增加,热导率的下降幅度逐渐增大。Sr掺杂显著改善Ca3Co4O9材料的热电性能,当掺杂量为0.5时获得最佳热电性能,573 K时Z值达1.07×10-4 K-1。

Polycrystalline Ca3-xSrxCo4O9（x=0-0.5） ceramics were prepared by the sol-gel method combined with the ordinary pressing sintering and the thermoelectric properties were measured from room temperature to 673 K.The Sr doping had a greater impact on the thermoelectric properties of Ca3Co4O9.The conductivity increased significantly as the Sr content increasing,and the Seebeck coefficient decreased slightly.Sr doping could reduce the thermal conductivity observably,and with the doping content increasing,the decrease amplitude of the thermal conductivity increased gradually.These results indicated that the thermoelectric properties of the material could be optimized remarkably with the Sr doping.The themoelectirc figure of merit Z reached 1.07×10-4 K-1 at 573 K for the sample of Ca2.5 Sr0.5Co4O9.