Mg_(3)Sb_(2)has attracted intensive attention as a typical Zintl-type thermoelectric material.Despite the exceptional thermoelectric performance in n-type Mg_(3)Sb_(2),the dimensionless figure of merit(zT)of p-type Mg...Mg_(3)Sb_(2)has attracted intensive attention as a typical Zintl-type thermoelectric material.Despite the exceptional thermoelectric performance in n-type Mg_(3)Sb_(2),the dimensionless figure of merit(zT)of p-type Mg_(3)Sb_(2)remains lower than 1,which is mainly attributed to its inferior electrical properties.Herein,we synergistically optimize the thermoelectric properties of p-type Mg_(3)Sb_(2)materials via codoping of Cd and Ag,which were synthesized by high-energy ball milling combined with hot pressing.It is found that Cd doping not only increases the carrier mobility of p-type Mg_(3)Sb_(2),but also diminishes its thermal conductivity(κ_(tot)),with Mg_(2.85)Cd_(0.5)Sb_(2)achieving a lowκtot value of∼0.67 W m^(−1)K^(−1)at room temperature.Further Ag doping elevates the carrier concentration,so that the power factor is optimized over the entire temperature range.Eventually,a peak zT of∼0.75 at 773 K and an excellent average zT of∼0.41 over 300−773 K are obtained in Mg_(2.82)Ag_(0.03)Cd_(0.5)Sb_(2),which are∼240%and∼490%higher than those of pristine Mg_(3.4)Sb_(2),respectively.This study provides an effective pathway to synergistically improve the thermoelectric performance of p-type Mg_(3)Sb_(2)by codoping Cd and Ag,which is beneficial to the future applications of Mg_(3)Sb_(2)-based thermoelectric materials.展开更多
A recent discovery of high-performance Mg_(3)Sb_(2) has ignited tremendous research activities in searching for novel Zintl-phase compounds as promising thermoelectric materials.Herein,a series of planar Zintl-phase X...A recent discovery of high-performance Mg_(3)Sb_(2) has ignited tremendous research activities in searching for novel Zintl-phase compounds as promising thermoelectric materials.Herein,a series of planar Zintl-phase XCuSb(X=Ca,Sr,Ba)thermoelectric materials are developed by vacuum induction melting.All these compounds exhibit high carrier mobilities and intrinsic low lattice thermal conductivities(below 1 W·m^(−1)·K^(−1) at 1010 K),resulting in peak p-type zT values of 0.14,0.30,and 0.48 for CaCuSb,SrCuSb,and BaCuSb,respectively.By using BaCuSb as a prototypical example,the origins of low lattice thermal conductivity are attributed to the strong interlayer vibrational anharmonicity of Cu–Sb honeycomb sublattice.Moreover,the first-principles calculations reveal that n-type BaCuSb can achieve superior thermoelectric performance with the peak zT beyond 1.1 because of larger conducting band degeneracy.This work sheds light on the high-temperature thermoelectric potential of planar Zintl compounds,thereby stimulating intense interest in the investigation of this unexplored material family for higher zT values.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 52071041, 11874356, 51802034)supported by the Key Research Program of Frontier Sciences, CAS (Grant No.QYZDB-SSW-SLH016)
文摘Mg_(3)Sb_(2)has attracted intensive attention as a typical Zintl-type thermoelectric material.Despite the exceptional thermoelectric performance in n-type Mg_(3)Sb_(2),the dimensionless figure of merit(zT)of p-type Mg_(3)Sb_(2)remains lower than 1,which is mainly attributed to its inferior electrical properties.Herein,we synergistically optimize the thermoelectric properties of p-type Mg_(3)Sb_(2)materials via codoping of Cd and Ag,which were synthesized by high-energy ball milling combined with hot pressing.It is found that Cd doping not only increases the carrier mobility of p-type Mg_(3)Sb_(2),but also diminishes its thermal conductivity(κ_(tot)),with Mg_(2.85)Cd_(0.5)Sb_(2)achieving a lowκtot value of∼0.67 W m^(−1)K^(−1)at room temperature.Further Ag doping elevates the carrier concentration,so that the power factor is optimized over the entire temperature range.Eventually,a peak zT of∼0.75 at 773 K and an excellent average zT of∼0.41 over 300−773 K are obtained in Mg_(2.82)Ag_(0.03)Cd_(0.5)Sb_(2),which are∼240%and∼490%higher than those of pristine Mg_(3.4)Sb_(2),respectively.This study provides an effective pathway to synergistically improve the thermoelectric performance of p-type Mg_(3)Sb_(2)by codoping Cd and Ag,which is beneficial to the future applications of Mg_(3)Sb_(2)-based thermoelectric materials.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52125103,52071041,U21A2054,and 12104071).
文摘A recent discovery of high-performance Mg_(3)Sb_(2) has ignited tremendous research activities in searching for novel Zintl-phase compounds as promising thermoelectric materials.Herein,a series of planar Zintl-phase XCuSb(X=Ca,Sr,Ba)thermoelectric materials are developed by vacuum induction melting.All these compounds exhibit high carrier mobilities and intrinsic low lattice thermal conductivities(below 1 W·m^(−1)·K^(−1) at 1010 K),resulting in peak p-type zT values of 0.14,0.30,and 0.48 for CaCuSb,SrCuSb,and BaCuSb,respectively.By using BaCuSb as a prototypical example,the origins of low lattice thermal conductivity are attributed to the strong interlayer vibrational anharmonicity of Cu–Sb honeycomb sublattice.Moreover,the first-principles calculations reveal that n-type BaCuSb can achieve superior thermoelectric performance with the peak zT beyond 1.1 because of larger conducting band degeneracy.This work sheds light on the high-temperature thermoelectric potential of planar Zintl compounds,thereby stimulating intense interest in the investigation of this unexplored material family for higher zT values.