放量制备Ba、Yb填充方钴矿(Ba,Yb)yCo4Sb12的热电性能

Thermoelectric Properties of Scaled-Up Double-Filled (Ba,Yb)yCo4Sb12 Skutterudites

摘要: 热电性能研究通常只需要制备2~3克材料，而热电器件的研制和应用需要大量的材料。为了获得放量制备的高性能热电材料，本文采用熔融、淬火、退火结合放电等离子烧结技术放量制备了Ba、Yb填充方钴矿(Ba,Yb)_yCo₄Sb₁₂，研究了Ba、Yb填充原子加入量对材料相组成、填充量及其热电性能的影响。结果表明，放量制备的(Ba,Yb)_yCo₄Sb₁₂填充方钴矿材料主要由方钴矿相和微量的YbSb组成；随着填充原子加入量增加，材料的实际填充量增大，电阻率、赛贝克系数绝对值减小，晶格热导率大幅度降低；放量制备的(Ba,Yb)_yCo₄Sb₁₂材料的最大ZT值达到1.31 (850 K时)，接近报道的最高值。

Abstract: It usually needs about two grams thermoelectric materials to study their performance, while more are needed to develop and apply their devices. To obtain high performance scaled up barium and ytterbium filled skutterudites, we scaled up (Ba,Yb)_yCo₄Sb₁₂ (y = 0.1, 0.12, 0.15) skutterudites by melting, quenching, annealing and spark plasma sintering, and studied the effects of the added amount of barium and ytterbium on the phase composition, filling fraction of barium and ytter- bium and thermoelectric properties of the materials. Results show that the scaled up (Ba,Yb)_yCo₄Sb₁₂ materials consist of mainly skutterudite phase and trace amount of YbSb phase. With the added amount of barium and ytterbium increasing, the real filling fraction of barium and ytterbium increases, the resistivity and the absolute Seebeck coefficient of the skutterudits decreases and the lattice thermal conductivity of the materials drops sharply. The maximum ZT for the (Ba,Yb)_yCo₄Sb₁₂ material reaches 1.31 at 850 K, close to the highest value reported.