TiFe_(1.1−x)Ni_(x)Sb的结构和热电性能随Ni填充量的演变  

Structure and thermoelectric property evolution of TiFe_(1.1−x)Ni_(x)Sb with the filling of Ni

作　　者：王晨心 董子睿 陈家俊 李志立 甘露 杨炯 张继业 骆军 Chenxin Wang;Zirui Dong;Jiajun Chen;Zhili Li;Lu Gan;Jiong Yang;Jiye Zhang;Jun Luo(School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China;Materials Genome Institute,Shanghai University,Shanghai 200444,China)

机构地区：[1]School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China [2]Materials Genome Institute,Shanghai University,Shanghai 200444,China

出　　处：《Science China Materials》2023年第8期3230-3237,共8页中国科学（材料科学（英文版）

基　　金：supported by the National Key Research and Development Program of China(2018YFA0702100);the National Natural Science Foundation of China(52272226,U21A2054,and 52072234).

摘　　要：TiFeSb是一种以half-Heusler结构为主相的多相材料.在这项工作中,我们发现可以通过将Ni填充到half-Heusler结构的4d空位来稳定TiFeSb,并获得单相TiFeNi_(0.1)Sb合金.为了提高热电性能,我们设计并合成了具有更多价电子的TiFe_(1.1−x)Ni_(x)Sb(x=0.1–1.0)样品.结构分析表明,x=0–0.3的样品是具有类half-Heusler结构的单相合金,x=0.4–0.7的样品是以Double half-Heusler为主相的两相材料,x=0.8–1.0的样品是类full-Heusler结构的单相材料.同时,在TiFe_(1.1−x)Ni_(x)Sb中实现了优异的p型(x=0–0.3)和n型(x=0.8–1.0)电输运性能,这可以用Slater-Pauling规则很好地解释.结合由于无序晶体结构而大大降低的晶格热导率,p型TiFe_(0.8)Ni_(0.3)Sb和n型TiFe_(0.3)Ni_(0.8)Sb在973 K下分别获得了约0.6和0.4的热电优值.我们还证明,这些样品的热电性能可以通过常规掺杂或合金化方法进一步优化.通过Cu代替Ni(或Fe),p型TiFe_(0.8)Ni_(0.2)Cu_(0.1)Sb的载流子浓度降低,并且在973 K时热电优值达到0.8,这是空位填充型Heusler合金的最高记录.TiFeSb is a multiphase material with the half-Heusler structure as the main phase.In this work,we discover that TiFeSb can be stabilized by filling Ni to the vacant 4d site of the half-Heusler structure,and a single-phase TiFeNi0.1Sb alloy is obtained.To improve the thermoelectric properties,TiFe_(1.1−x)Ni_(x)Sb(x=0.1–1.0)samples with more valence electrons are designed and synthesized.Structural analysis reveals that the samples with x=0–0.3 are single-phase alloys with the half-Heusler-like structure,the samples with x=0.4–0.7 are two-phase materials with the double half-Heusler as the main phase,and the samples with x=0.8–1.0 are single-phase alloys with the full-Heusler-like structure.Meanwhile,both promising p-type(x=0–0.3)and n-type(x=0.8–1.0)electrical properties are realized in TiFe_(1.1−x)Ni_(x)Sb,which can be well explained by the Slater-Pauling rule.In combination with greatly reduced lattice thermal conductivity owing to the disordered crystal structure,the p-type TiFe_(0.8)Ni_(0.3)Sb and ntype TiFe_(0.3)Ni_(0.8)Sb achieve dimensionless thermoelectric figure of merits zT about 0.6 and 0.4 at 973 K,respectively.We also demonstrate that the thermoelectric properties of these samples can be further optimized by conventional doping or alloying methods.By replacing Ni(or Fe)with Cu,the carrier concentration of p-type TiFe_(0.8)Ni_(0.2)Cu_(0.1)Sb is decreased,and the zT value reaches 0.8 at 973 K,which is the record of vacancy-filled Heusler alloys.

关 键 词：HEUSLER合金 热电性能 热电优值 多相材料 晶格热导率 两相材料 填充量 填充型 

分 类 号：TG132[一般工业技术—材料科学与工程]