Nanocomposite is proved to be an effective method to improve thermoelectric performance.In the present study,graphene is introduced into p-type skutterudite La0.8Ti0.1Ga0.1Fe3CoSb12 by plasma-enhanced chemical vapor d...Nanocomposite is proved to be an effective method to improve thermoelectric performance.In the present study,graphene is introduced into p-type skutterudite La0.8Ti0.1Ga0.1Fe3CoSb12 by plasma-enhanced chemical vapor deposition（PECVD）method to form skutterudite/graphene nanocomposites.It is demonstrated that the graphene has no obvious effect on the electrical conductivity of La0.8Ti0.1Ga0.1Fe3CoSb12,but the Seebeck coefficient is slightly improved at high temperature,thereby leading to high power factor.Furthermore,due to the enhancement of phonon scattering by the graphene,the lattice thermal conductivity is reduced significantly.Ultimately,the maximum z T value of La0.8Ti0.1Ga0.1Fe3CoSb12/graphene is higher than that of graphene-free alloy and reaches to 1.0 at 723 K.Such an approach raised by us enriches prospects for future practical application.展开更多
Skutterudite CoAs3 is a potentially important thermoelectric material. Morse potential is employed here to carry out molecular dynamics simulations of nanobulk CoAs3 at the temperature of 0 K. The stress-strain relati...Skutterudite CoAs3 is a potentially important thermoelectric material. Morse potential is employed here to carry out molecular dynamics simulations of nanobulk CoAs3 at the temperature of 0 K. The stress-strain relationships under uniaxial tensile and/or compressive strain are obtained. The elastic modulus, extreme strength and deformation mechanism are studied. The simulation results indicate that nanobulk CoAs3 abruptly ruptures at much higher strain level under tension than conventional bulk CoAs3. Both the extreme stresses under tension and compression are much higher than those of conventional bulk CoAs3.展开更多
Nanostructured skutterudite-related compound Fe0.25Ni0.25Co0.5Sb3 was synthesized by a solvothermal method using FeCl3, NiCl2, CoCl2, and SbCl3 as the precursors and NaBH4 as the reductant. The solvothermally synthesi...Nanostructured skutterudite-related compound Fe0.25Ni0.25Co0.5Sb3 was synthesized by a solvothermal method using FeCl3, NiCl2, CoCl2, and SbCl3 as the precursors and NaBH4 as the reductant. The solvothermally synthesized powders consisted of fine granules with an average particle size of tens of nanometers. The bulk material was prepared by hot pressing the powders. Transport property measurements indicated a heavily doped semiconductor behavior with n-type conduction. The thermal conductivity is about 1.83 W·m-1·K-1 at room temperature and decreases to 1.57 W·m-1·K-1 at 673 K. The low thermal conductivity is attributed to small grain size and high porosity. A maximum dimensionless figure of merit of 0.15 is obtained at 673 K.展开更多
Polycrystalline samples of Sm partially filled skutterudites SmyFexCo4-xSb12 were prepared by melting and Spark Plasma Sintering technique. The results of Rietveld refinement showed that the obtained SmyFexCo4-xSb12 s...Polycrystalline samples of Sm partially filled skutterudites SmyFexCo4-xSb12 were prepared by melting and Spark Plasma Sintering technique. The results of Rietveld refinement showed that the obtained SmyFexCo4-xSb12 samples possessed filled skutterudite structures. The thermal parameter （B） of Sm is larger than that of Sb, Fe, and Co, indicating that Sm ＂rattled＂ in Sb-icosahedron voids. The effects of filling atom Sm on thermoelectric properties of these compounds were investigated. With the increase of Sm filling fraction （y）, electrical conductivity decreased, Seebeck coefficient increased and had a maximum value when y was 0.38; thermal conductivity reduced and had a minimum value when y was 0. 32. At 750 K, the highest figure of merit of 0.68 was obtained for Sm0.32Fe1.47Co2.53Sb12.展开更多
Full-PotentiaJ Linearized Augmented Plane Wave plus locaJ orbital method （FPLAPW ＋10） calculations are performed for ThFe4P12 in the filled skutterudite in order to investigate the optical properties and to show th...Full-PotentiaJ Linearized Augmented Plane Wave plus locaJ orbital method （FPLAPW ＋10） calculations are performed for ThFe4P12 in the filled skutterudite in order to investigate the optical properties and to show the origin of the different optical transitions. It is found that the band gap is indirect for ThFe4P12. Then the contributions of the different transition peaks are analyzed from the imaginary part of the dielectric function. In contrast to recent experimental expectations, our calculations are in good agreement with experimental reflection spectra and ε1 （ω） spectrum.展开更多
The correlations among composition, structure, chemical bond andthermoelectric property of skutterudites CoSb_3 and CeCo_5Fe_3Sb_12have been studied by using density function and discrete variation(DFT- DVM) method. T...The correlations among composition, structure, chemical bond andthermoelectric property of skutterudites CoSb_3 and CeCo_5Fe_3Sb_12have been studied by using density function and discrete variation(DFT- DVM) method. Three models for this study were proposed andcalculated by which the 'rattling' pattern was Described. Model 1 iswith Ce in the center, model 2 is with Ce away the center and near toSb, and model 3 is Also with Ce away the center but near to Fe. Thecalculated results show that in model 3, the ionic bond is theStrongest, but the covalent bond is the weakest.展开更多
The binary CoSb_(3) skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit, ZT, is very low. The thermal conductivity of C...The binary CoSb_(3) skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit, ZT, is very low. The thermal conductivity of CoSb_(3) materials can be significantly reduced through phonon engineering, such as low-dimensional structure, the introduction of nano second phases,nanointerfaces or nanopores, which greatly improves their ZT values. The phonon engineering can optimize significantly the thermal transport properties of CoSb_(3)-based materials. However, the improvement of the electronic transport properties is not obvious, or even worse. Energy band and charge-carrier engineering can significantly improve the electronic transport properties of CoSb_(3)-based materials while optimizing the thermal transport properties. Therefore, the decoupling of thermal and electronic transport properties of CoSb_(3)-based materials can be realized by energy band and charge-carrier engineering. This review summarizes some methods of optimizing synergistically the electronic and thermal transport properties of CoSb_(3) materials through the energy band and charge-carrier engineering strategies. Energy band engineering strategies include band convergence or resonant energy levels caused by doping/filling. The charge-carrier engineering strategy includes the optimization of carrier concentration and mobility caused by doping/filling, forming modulation doped structures or introducing nano second phase. These strategies are effective means to improve performance of thermoelectric materials and provide new research ideas of development of high-efficiency thermoelectric materials.展开更多
Nanostructures enhance phonon scattering and improve the figure of merit of thermoelectric materials. Nanosized CoSb3 skutterudite was synthesized by solvothermal methods using CoCl2 and SbCl3 as the precursors. A ...Nanostructures enhance phonon scattering and improve the figure of merit of thermoelectric materials. Nanosized CoSb3 skutterudite was synthesized by solvothermal methods using CoCl2 and SbCl3 as the precursors. A 'two-step' model was suggested for the formation of CoSb3 based on the X-ray diffraction analysis. The first step is the formation of cobalt diantimonide in the earlier stage during the synthesis process. Diantimonide was then combined with antimony atoms to form the skutterudite structured triantimonide, CoSb3, in the later stage of the synthesis process as the second step. The synthesized CoSb3 powders consist of irregular particles with sizes of about 20 nm and sheets of about 80nm.展开更多
We report the synthesis of Nd-filled and Fe substituted p-type Ndx Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）（x=0.5,0.6,0.7,0.8,and 0.9）skutterudites by the solid-state reaction method.The influences of Nd filler ...We report the synthesis of Nd-filled and Fe substituted p-type Ndx Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）（x=0.5,0.6,0.7,0.8,and 0.9）skutterudites by the solid-state reaction method.The influences of Nd filler on the electrical and thermal transport prop-erties are investigated in a temperature range from room temperature to 850 K.A lowest lattice thermal conductivity of 0.88 W·m^-1·K^-1 is obtained in Nd0.8Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）at 673 K,which results from the localized vibration modes of fillers and the increase of grains boundaries.Meanwhile,the maximum power factor is 2.77 m W·m^-1·K^-2 for the Nd（0.9）Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）sample at 668 K.Overall,the highest dimensionless figure of merit z T=0.87 is achieved at 714 Kfor Nd（0.9）Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51622101,51771065,and 51471061)
文摘Nanocomposite is proved to be an effective method to improve thermoelectric performance.In the present study,graphene is introduced into p-type skutterudite La0.8Ti0.1Ga0.1Fe3CoSb12 by plasma-enhanced chemical vapor deposition（PECVD）method to form skutterudite/graphene nanocomposites.It is demonstrated that the graphene has no obvious effect on the electrical conductivity of La0.8Ti0.1Ga0.1Fe3CoSb12,but the Seebeck coefficient is slightly improved at high temperature,thereby leading to high power factor.Furthermore,due to the enhancement of phonon scattering by the graphene,the lattice thermal conductivity is reduced significantly.Ultimately,the maximum z T value of La0.8Ti0.1Ga0.1Fe3CoSb12/graphene is higher than that of graphene-free alloy and reaches to 1.0 at 723 K.Such an approach raised by us enriches prospects for future practical application.
基金Funded by 973 Program(No.2007CB607506)the National Natural Science Foundation of China(No.10672127)the Ministryof Education of China(No.NCET-04-0725)
文摘Skutterudite CoAs3 is a potentially important thermoelectric material. Morse potential is employed here to carry out molecular dynamics simulations of nanobulk CoAs3 at the temperature of 0 K. The stress-strain relationships under uniaxial tensile and/or compressive strain are obtained. The elastic modulus, extreme strength and deformation mechanism are studied. The simulation results indicate that nanobulk CoAs3 abruptly ruptures at much higher strain level under tension than conventional bulk CoAs3. Both the extreme stresses under tension and compression are much higher than those of conventional bulk CoAs3.
基金supported by the National Basic Research Program of China (No. 2007CB607502)the Key Program of National Natural Science Foundation of China (No. 50731006)
文摘Nanostructured skutterudite-related compound Fe0.25Ni0.25Co0.5Sb3 was synthesized by a solvothermal method using FeCl3, NiCl2, CoCl2, and SbCl3 as the precursors and NaBH4 as the reductant. The solvothermally synthesized powders consisted of fine granules with an average particle size of tens of nanometers. The bulk material was prepared by hot pressing the powders. Transport property measurements indicated a heavily doped semiconductor behavior with n-type conduction. The thermal conductivity is about 1.83 W·m-1·K-1 at room temperature and decreases to 1.57 W·m-1·K-1 at 673 K. The low thermal conductivity is attributed to small grain size and high porosity. A maximum dimensionless figure of merit of 0.15 is obtained at 673 K.
基金Project supported by the National Natural Science Foundation of China (50372049)the Major International Cooperation Program of the National Natural Science Foundation of China (50310353)
文摘Polycrystalline samples of Sm partially filled skutterudites SmyFexCo4-xSb12 were prepared by melting and Spark Plasma Sintering technique. The results of Rietveld refinement showed that the obtained SmyFexCo4-xSb12 samples possessed filled skutterudite structures. The thermal parameter （B） of Sm is larger than that of Sb, Fe, and Co, indicating that Sm ＂rattled＂ in Sb-icosahedron voids. The effects of filling atom Sm on thermoelectric properties of these compounds were investigated. With the increase of Sm filling fraction （y）, electrical conductivity decreased, Seebeck coefficient increased and had a maximum value when y was 0.38; thermal conductivity reduced and had a minimum value when y was 0. 32. At 750 K, the highest figure of merit of 0.68 was obtained for Sm0.32Fe1.47Co2.53Sb12.
基金The project supported by the Natural Science Foundation of Hubei Province under Grant No.2003ABA004
文摘Full-PotentiaJ Linearized Augmented Plane Wave plus locaJ orbital method （FPLAPW ＋10） calculations are performed for ThFe4P12 in the filled skutterudite in order to investigate the optical properties and to show the origin of the different optical transitions. It is found that the band gap is indirect for ThFe4P12. Then the contributions of the different transition peaks are analyzed from the imaginary part of the dielectric function. In contrast to recent experimental expectations, our calculations are in good agreement with experimental reflection spectra and ε1 （ω） spectrum.
基金Funded by the Open Foundation of State Key of Lab.Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology,and Science Foundation of Hubei Province(No. 98J028)
文摘The correlations among composition, structure, chemical bond andthermoelectric property of skutterudites CoSb_3 and CeCo_5Fe_3Sb_12have been studied by using density function and discrete variation(DFT- DVM) method. Three models for this study were proposed andcalculated by which the 'rattling' pattern was Described. Model 1 iswith Ce in the center, model 2 is with Ce away the center and near toSb, and model 3 is Also with Ce away the center but near to Fe. Thecalculated results show that in model 3, the ionic bond is theStrongest, but the covalent bond is the weakest.
基金supported by the National Natural Science Foundation of China (Grant No. 51872006)the Excellent Youth Project of Natural Science Foundation of Anhui Province of China (Grant No. 2208085Y17)。
文摘The binary CoSb_(3) skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit, ZT, is very low. The thermal conductivity of CoSb_(3) materials can be significantly reduced through phonon engineering, such as low-dimensional structure, the introduction of nano second phases,nanointerfaces or nanopores, which greatly improves their ZT values. The phonon engineering can optimize significantly the thermal transport properties of CoSb_(3)-based materials. However, the improvement of the electronic transport properties is not obvious, or even worse. Energy band and charge-carrier engineering can significantly improve the electronic transport properties of CoSb_(3)-based materials while optimizing the thermal transport properties. Therefore, the decoupling of thermal and electronic transport properties of CoSb_(3)-based materials can be realized by energy band and charge-carrier engineering. This review summarizes some methods of optimizing synergistically the electronic and thermal transport properties of CoSb_(3) materials through the energy band and charge-carrier engineering strategies. Energy band engineering strategies include band convergence or resonant energy levels caused by doping/filling. The charge-carrier engineering strategy includes the optimization of carrier concentration and mobility caused by doping/filling, forming modulation doped structures or introducing nano second phase. These strategies are effective means to improve performance of thermoelectric materials and provide new research ideas of development of high-efficiency thermoelectric materials.
文摘Nanostructures enhance phonon scattering and improve the figure of merit of thermoelectric materials. Nanosized CoSb3 skutterudite was synthesized by solvothermal methods using CoCl2 and SbCl3 as the precursors. A 'two-step' model was suggested for the formation of CoSb3 based on the X-ray diffraction analysis. The first step is the formation of cobalt diantimonide in the earlier stage during the synthesis process. Diantimonide was then combined with antimony atoms to form the skutterudite structured triantimonide, CoSb3, in the later stage of the synthesis process as the second step. The synthesized CoSb3 powders consist of irregular particles with sizes of about 20 nm and sheets of about 80nm.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674040,11404044,51472036,51672270,and 51401202)the Fundamental Research Funds for the Central Universities(Grant No.106112016CDJZR308808)+1 种基金the 100 Talent Program of the Chinese Academy of Sciences(Grant No.2013-46)the Project for Fundamental and Frontier Research in Chongqing,China(Grant No.CSTC2015JCYJBX0026)
文摘We report the synthesis of Nd-filled and Fe substituted p-type Ndx Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）（x=0.5,0.6,0.7,0.8,and 0.9）skutterudites by the solid-state reaction method.The influences of Nd filler on the electrical and thermal transport prop-erties are investigated in a temperature range from room temperature to 850 K.A lowest lattice thermal conductivity of 0.88 W·m^-1·K^-1 is obtained in Nd0.8Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）at 673 K,which results from the localized vibration modes of fillers and the increase of grains boundaries.Meanwhile,the maximum power factor is 2.77 m W·m^-1·K^-2 for the Nd（0.9）Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）sample at 668 K.Overall,the highest dimensionless figure of merit z T=0.87 is achieved at 714 Kfor Nd（0.9）Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）.
