In0.3Co4Sb12-xSex 方钴矿热电材料的制备和热电性能

用熔融退火结合放电等离子烧结法制备了In_0.3Co₄Sb_12-xSe_x(x=0—0.3)方钴矿热电材料,探讨了In的存在形式,系统研究了Se掺杂量对结构和热电性能的影响.结果表明:In可以填充到方钴矿二十面体空洞处,过量In在晶界处形成InSb第二相,Se对Sb的置换使晶格常数减小,In填充上限降低;In_0.3Co₄Sb_12-xSe_x样品呈n型传导,随着Se掺杂量的增大,载流子浓度降低,电导率下降,Seebeck系数增大,功率因子有所降低;由于在结构中引入了质量波动及晶格畸变,适量的Se掺杂可以大幅降低材料晶格热导率;样品In_0.3Co₄Sb₁₂和In_0.3Co₄Sb_11.95Se_0.05的最大ZT值均达到1.0以上. 关键词： 掺杂 填充式方钴矿 热电性能

Synthesis and thermoelectric properties of thermoelectric materials of the skutterudites In0.3Co4 Sb12-xSex

Thermoelectric materials of the skutterudites In_0.3Co₄Sb_12-xSe_x(x=0—0.3) were prepared by melt-annealing and spark plasma sintering. The existence forms of the element In were investigated, and the effect of doping Se in In filled-skutterudites on the structure and thermoelectric properties were also studied systematically. The element In could be filled into the hole structure of skutterudite, and the excessive In exists as InSb in the boundary of grains. After the substitution of Se for Sb, the lattice parameters decrease, and the filling fraction limit of In decreases. All the compounds of In_0.3Co₄Sb_12-xSe_x(x=0—0.3) show n-type conduction. With the Se doping amount increasing, the carrier concentration and electrical conductivity decrease, and the Seebeck coefficient increases, and the power factor decreases slightly. Since the introduction of Se substitution brings about quality fluctuation and lattice distortion in structure, moderate amount of Se substitution can lower the thermal conductivity largely. The maximum ZT values of both In_0.3Co₄Sb₁₂ and In_0.3Co₄Sb_11.95Se_0.05 samples reach above 1.0.