CoSb3-based mark mid-temperature skutterudites have been a benchthermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal latti...CoSb3-based mark mid-temperature skutterudites have been a benchthermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal lattice constant of CoSb3 in the context of ＂chemical pressure.＂ In this work, we employed ab initio density functional theory in conjunction with semiclassical Boltzmann transport theory to investigate the mechanical properties and especially how hydrostatic loadings, i.e., ＂physical pressure,＂ impact the electronic band structure, Seebeck coefficient, and power factor of pristine CoSb3. It is found that hydrostatic pressure enlarges the band gap, suppresses the density of states （DOS） near the valence band edge, and fosters the band convergence between the valley bands and the conduction band minimum （CBM）. By contrast, hydrostatic tensile reduces the band gap, increases the DOS near the valence band edge, and diminishes the valley bands near the CBM. Therefore, applying hydrostatic pressure provides an alternative avenue for achieving band convergence to improve thermoelectric properties of N-type CoSb3, which is further supported by our carrier concentration studies. These results provide valuable insight into the further improvement of thermoelectric performance of CoSb3-based skutterudites via a synergy of physical and chemical pressures.展开更多
CoSb3 nanowire arrays, preferred orientation of [510], were fabricated by electrodeposition of Co2+ and Sb3+ into anodic aluminum oxide (AAO) templates. The morphologies, structure, and composition of the as-synthesiz...CoSb3 nanowire arrays, preferred orientation of [510], were fabricated by electrodeposition of Co2+ and Sb3+ into anodic aluminum oxide (AAO) templates. The morphologies, structure, and composition of the as-synthesized sample have been performed using X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). Based on the previous investigation on CoSb3 nanowire arrays orientated along [420], the formation mechanism for different preferential orientation nanowire arrays was discussed.展开更多
Molecular dynamics simulations are implemented to study the mechanical fracture of CoSb3 with penetrated nanocracks under the mode-Ⅰ stress.The crack surface and crack front direction are(100)and[001],respectively.It...Molecular dynamics simulations are implemented to study the mechanical fracture of CoSb3 with penetrated nanocracks under the mode-Ⅰ stress.The crack surface and crack front direction are(100)and[001],respectively.It is found that,at a fixed initial crack length,the fracture strength varies with the sample size,but the calculated value of fracture toughness KIC,by employing the classical formula of linear elastic fracture mechanics,maintains constant.When the crack is short in length relative to the sample,the variation of the fracture strength with the initial crack length is well fitted mathematically,and the extrapolation shows rationality even up to the macroscale.More general analyses reveal that,the fracture toughness increases monotonically with increasing the initial crack length until reaching the limit,and the increment is particularly noticeable below 36 nm.Furthermore,different atomic configurations at the crack tip are considered,which show an evident influence on the strength of nano-cracked CoSb3.展开更多
Bulk CoSb3 with single phase was synthesized by mechanical alloying and spark plasma sintering （MA-SPS）. The thermoelectric properties of bulk CoSb3 prepared by different technologies were investigated. All samples ...Bulk CoSb3 with single phase was synthesized by mechanical alloying and spark plasma sintering （MA-SPS）. The thermoelectric properties of bulk CoSb3 prepared by different technologies were investigated. All samples have the character of typical semiconductor electricity and their thermoelectric figures of merit （ZT） get the maximum values at 400℃. The highest ZT value is 0.0571, belonging to the sample sintered at 600℃ among all samples at all temperatures.展开更多
The polyaniline （PAni）/polyvinylidene fluoride （PVDF） hybrid was served as a novel binder for CoSb3-based alloy electrode. The effect of PAni content on the electrochemical performances of the alloy electrode was ...The polyaniline （PAni）/polyvinylidene fluoride （PVDF） hybrid was served as a novel binder for CoSb3-based alloy electrode. The effect of PAni content on the electrochemical performances of the alloy electrode was investigated. It was found that the CoSb3 electrode using the binary PAni/PVDF binder exhibits higher reversible capacity than that using the single PVDF binder, especially in the initial cycles. As a result, the PAni/PVDF hybrid could be a promising binder for the alloy electrode.展开更多
Intermetallic compound CoSb 3 powders were prepared by vacuum melting and ball milling. It is found that the reversible capacity of the CoSb 3 electrode is about 470?mA·h/g at the first cycle with the potential p...Intermetallic compound CoSb 3 powders were prepared by vacuum melting and ball milling. It is found that the reversible capacity of the CoSb 3 electrode is about 470?mA·h/g at the first cycle with the potential plateaus from 0.8?V to 1.0?V against the pure lithium electrode. 10% mesocarbon microbead (MCMB) (mass fraction) additives can improve both capacity and cycling life of CoSb 3, while the effect of carbon nanotube (CNT) additives is not visible.展开更多
基金Guizhou Provincial Department of Education Foundation(Qianjiaohe KYzi[2016]102)National Natural Science Foundation of China(51764005)Liupanshui Science and Technology Foundation(52020-2018-04-05)
基金supported by the Office of Science of the US Department of Energy (Nos. DEAC05-00OR22750 and DE-AC02-05-CH11231)the support of National Science Foundation (No. DMR-1307740)
文摘CoSb3-based mark mid-temperature skutterudites have been a benchthermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal lattice constant of CoSb3 in the context of ＂chemical pressure.＂ In this work, we employed ab initio density functional theory in conjunction with semiclassical Boltzmann transport theory to investigate the mechanical properties and especially how hydrostatic loadings, i.e., ＂physical pressure,＂ impact the electronic band structure, Seebeck coefficient, and power factor of pristine CoSb3. It is found that hydrostatic pressure enlarges the band gap, suppresses the density of states （DOS） near the valence band edge, and fosters the band convergence between the valley bands and the conduction band minimum （CBM）. By contrast, hydrostatic tensile reduces the band gap, increases the DOS near the valence band edge, and diminishes the valley bands near the CBM. Therefore, applying hydrostatic pressure provides an alternative avenue for achieving band convergence to improve thermoelectric properties of N-type CoSb3, which is further supported by our carrier concentration studies. These results provide valuable insight into the further improvement of thermoelectric performance of CoSb3-based skutterudites via a synergy of physical and chemical pressures.
文摘CoSb3 nanowire arrays, preferred orientation of [510], were fabricated by electrodeposition of Co2+ and Sb3+ into anodic aluminum oxide (AAO) templates. The morphologies, structure, and composition of the as-synthesized sample have been performed using X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). Based on the previous investigation on CoSb3 nanowire arrays orientated along [420], the formation mechanism for different preferential orientation nanowire arrays was discussed.
基金funding was provided by the National Natural Science Foundation of China(No.51972253).
文摘Molecular dynamics simulations are implemented to study the mechanical fracture of CoSb3 with penetrated nanocracks under the mode-Ⅰ stress.The crack surface and crack front direction are(100)and[001],respectively.It is found that,at a fixed initial crack length,the fracture strength varies with the sample size,but the calculated value of fracture toughness KIC,by employing the classical formula of linear elastic fracture mechanics,maintains constant.When the crack is short in length relative to the sample,the variation of the fracture strength with the initial crack length is well fitted mathematically,and the extrapolation shows rationality even up to the macroscale.More general analyses reveal that,the fracture toughness increases monotonically with increasing the initial crack length until reaching the limit,and the increment is particularly noticeable below 36 nm.Furthermore,different atomic configurations at the crack tip are considered,which show an evident influence on the strength of nano-cracked CoSb3.
文摘Bulk CoSb3 with single phase was synthesized by mechanical alloying and spark plasma sintering （MA-SPS）. The thermoelectric properties of bulk CoSb3 prepared by different technologies were investigated. All samples have the character of typical semiconductor electricity and their thermoelectric figures of merit （ZT） get the maximum values at 400℃. The highest ZT value is 0.0571, belonging to the sample sintered at 600℃ among all samples at all temperatures.
文摘The polyaniline （PAni）/polyvinylidene fluoride （PVDF） hybrid was served as a novel binder for CoSb3-based alloy electrode. The effect of PAni content on the electrochemical performances of the alloy electrode was investigated. It was found that the CoSb3 electrode using the binary PAni/PVDF binder exhibits higher reversible capacity than that using the single PVDF binder, especially in the initial cycles. As a result, the PAni/PVDF hybrid could be a promising binder for the alloy electrode.
文摘Intermetallic compound CoSb 3 powders were prepared by vacuum melting and ball milling. It is found that the reversible capacity of the CoSb 3 electrode is about 470?mA·h/g at the first cycle with the potential plateaus from 0.8?V to 1.0?V against the pure lithium electrode. 10% mesocarbon microbead (MCMB) (mass fraction) additives can improve both capacity and cycling life of CoSb 3, while the effect of carbon nanotube (CNT) additives is not visible.
