Shanyu Wang
Wuhan University of Technology
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Featured researches published by Shanyu Wang.
Nano Letters | 2010
Wenjie Xie; Jian He; Hye Jung Kang; Xinfeng Tang; Song Zhu; Mark Laver; Shanyu Wang; J. R. D. Copley; Craig M. Brown; Qingjie Zhang; Terry M. Tritt
Herein, we report the synthesis of multiscale nanostructured p-type (Bi,Sb)(2)Te(3) bulk materials by melt-spinning single elements of Bi, Sb, and Te followed by a spark plasma sintering process. The samples that were most optimized with the resulting composition (Bi(0.48)Sb(1.52)Te(3)) and specific nanostructures showed an increase of approximately 50% or more in the figure of merit, ZT, over that of the commercial bulk material between 280 and 475 K, making it suitable for commercial applications related to both power generation and refrigeration. The results of high-resolution electron microscopy and small angle and inelastic neutron scattering along with corresponding thermoelectric property measurements corroborate that the 10-20 nm nanocrystalline domains with coherent boundaries are the key constituent that accounts for the resulting exceptionally low lattice thermal conductivity and significant improvement of ZT.
Journal of Materials Science | 2013
Wenjie Xie; Shanyu Wang; Song Zhu; Jian He; Xinfeng Tang; Qingjie Zhang; Terry M. Tritt
The last decade has witnessed nanocomposites becoming a new paradigm in the field of thermoelectric (TE) research. At its core is to prepare high performance TE nanocomposites, both p- and n-type, in a time and energy efficient way. To this end, we in this article summarize our recent effort and results on both p- and n-type Bi2Te3-based nanocomposites prepared by a unique single-element-melt-spinning spark-plasma sintering procedure. The results of transport measurements, scanning and transmission electronic microscopy, and small angle neutron scattering have proved essential in order to establish the correlation between the nanostructures and the TE performance of the materials. Interestingly, we find that in situ formed nanocrystals with coherent boundaries are the key nanostructures responsible for the significantly improved TE performance of p-type Bi2Te3 nanocomposites whereas similar nanostructures turn out to be less effective for n-type Bi2Te3 nanocomposites. We also discuss the alternative strategies to further improve the TE performance of n-type Bi2Te3 materials via nanostructuring processes.
Journal of Materials Chemistry | 2013
Gangjian Tan; Wei Liu; Shanyu Wang; Yonggao Yan; Han Li; Xinfeng Tang; Ctirad Uher
In this work, we adopt a non-equilibrium melt spinning technique combined with a subsequent spark plasma sintering technique to successfully synthesize a p-type nanostructured CeFe4Sb12 skutterudite compound with high homogeneity in less than 24 hours. Microstructures of the melt-spun ribbons and the sintered bulk material are systematically investigated. The evolution of multiple-phase melt-spun ribbons into a single-phase skutterudite compound during the heating process is also carefully examined. Greatly refined matrix grains (300–500 nm) and numerous FeSb2 nanodots with sizes below 50 nm are evenly distributed inside the grains, and together contribute to the experimentally observed low lattice thermal conductivity of the sintered bulk material. Both absolute and average ZT values of this melt-spun skutterudite are about 10% higher than in the material of the same composition prepared by traditional melting and long-term annealing. The markedly shortened preparation time coupled with the enhanced thermoelectric performance should make this synthesis process of interest for commercial applications.
Journal of Materials Chemistry | 2012
Shanyu Wang; X. J. Tan; Gangjian Tan; Wei Liu; Han Li; Huijun Liu; Xinfeng Tang
In this study, we demonstrate a realization of a favorable modification of band structures and an apparent increase in the density of state effective mass in β-Zn4Sb3 compound by introduction of a slight amount of Ge at the Zn site, in a manner of adding a shape peak below the valence band edge and giving rise to a significant enhancement in the power factor which is similar to the case of Tl-doped PbTe. As a consequence, the high power factor exceeding 1.4 mW m−1 K−2, coupled with the intrinsic very low thermal conductivity originated from complex crystal structures and a high degree of disorder, results in a maximum figure of merit of ∼1.35 at 680 K for the 0.25 at% Ge-substituted sample, which is ∼20% improvement as compared with that of the unsubstituted sample in this study. What is most important is the average ZT between 300 and 680 K reaches ∼1.0, which is ∼35% enhancement in comparison with the unsubstituted sample and superior to most of p-type materials in this temperature range. Furthermore, the combination of high thermoelectric performance and improvement in the thermodynamic properties makes this natural-abundant, “non-toxic” and cheap Ge-substituted β-Zn4Sb3 compound a very promising candidate for thermoelectric energy applications.
Journal of Physics D | 2014
Yun Zheng; Shanyu Wang; Wei Liu; Zhongjie Yin; Han Li; Xinfeng Tang; Ctirad Uher
In this study, a series of p-type Ag-doped PbS compounds were prepared by a vacuum melting combined with subsequent spark plasma sintering process. Ag partially occupies Pb sites acting as an electron acceptor to increase the hole concentration, and also in situ forms Ag2S nanoprecipitates at the grain boundaries which are detectable in thermal analysis and microstructural observations. The two existences of Ag both exert significant influences on the electrical transport properties. With increasing temperature, dissolution of Ag2S nanoprecipitates into the PbS matrix as interstitial Ag gradually decreases the hole concentration. Very low mobility of Ag-doped samples is unexpected at low temperatures, which indicates a strong carrier scattering. From temperature dependent mobility, it can be concluded that neutral impurity scattering (μ ~ Ta, a = 0) dominates at low temperature (T 1.5) governs until lattice vibrations take over at T > 450 K (a ~ −2.5). The complex scattering mechanisms at T < 450 K in Ag-doped samples should be originated from the multiple existences of Ag (Ag+, interstitial Ag, Ag2S nanoprecipitates). In particular, Ag doping increases the high temperature electrical conductivity, giving rise to an enhanced power factor of ~0.8 × 10−3 W m−1 K−2 at 870 K for the 1.5 at% Ag-doped sample. Benefiting from the improved power factor and low lattice thermal conductivity originating from strong lattice anharmonicity, a doubled ZT value of ~0.6 can be achieved for Pb0.985Ag0.015S in comparison to that of pristine PbS.
Intermetallics | 2011
Shanyu Wang; Wenjie Xie; Han Li; Xinfeng Tang
Acta Materialia | 2010
Wenjie Xie; Jian He; Song Zhu; Xianli Su; Shanyu Wang; Tim Holgate; J.W. Graff; V. Ponnambalam; S.J. Poon; Xinfeng Tang; Qingjie Zhang; Terry M. Tritt
Journal of Physics D | 2010
Shanyu Wang; Wenjie Xie; Han Li; Xinfeng Tang
Acta Materialia | 2011
Shanyu Wang; Han Li; Dekui Qi; Wenjie Xie; Xinfeng Tang
Acta Materialia | 2013
Gangjian Tan; Wei Liu; Hang Chi; Xianli Su; Shanyu Wang; Yonggao Yan; Xinfeng Tang; Winnie Wong-Ng; Ctirad Uher