贵金属的热电性能和热电偶材料

本文评述了贵金属的热电性能。金、银的绝对热电势率为正;铂族金属为负;钯、铂等过渡族元素与银、金的合金存在有负的极大值;银、金中含有极少量的铁磁性金属(如铁、钴、镍)杂质,在低温下将出现巨大的负的热电势率。文中还系统介绍了铂铑系、铱铑系和钯基合金等高温热电偶材料以及金铁、金钴等低温热电偶材料。     

Bi-Te基热电材料的研究进展

阐述了Bi2Te3热电材料的基本特性,评述了Se,TeL,SiC,RE(La,Ce等)的掺杂对BiTe材料热电性能的影响,以及国内外掺杂Bi-Te基热电材料的研究进展.介绍了Bi-Te基合金的制备技术的发展.最后指出通过材料的结构优化、组分调整及制备技术的改进,可以进一步提高材料的热电性能,得到理想的热电优值.     

钯基合金膜应用研究进展

综述了钯基合金膜应用研究的进展状况 ,着重介绍了钯合金膜的制备方法、影响钯合金膜渗氢性能的因素等 ,并对钯基合金膜存在的技术问题及其发展方向进行了讨论 .     

PbTe_(0.8)Se_(0.2)基热电材料载流子浓度优化与Mg合金化

PbTe基合金是目前性能最好的中温区热电材料,近年来受到广泛关注。本文研究了载流子浓度对Na掺杂PbTe0.8Se0.2合金热电性能的影响,在Na含量为2%时,ZT可以达到1.73。在此基础上,利用Mg合金化降低材料晶格热导率的作用,进一步提升材料的热电性能。结果表明,在Mg含量为1~3%的时,ZT值在800K附近都达到了2.0左右。     

贵金属精密电阻合金的进展

本文全面评述国内外贵金属精密电阻合金的进展,重点放在最近二、三十年。首先简要回顾该材料的整个发展过程。接着分铂基、钯基、金-钯基、金基和银基合金5部分详细评述贵金属精密电阻合金的进展状况,指出该材料领域围绕着“高可靠、高耐磨”这个基本方向而出现的两个动向：即高电阻率、低电阻温度系数的钯基合金,特别是金-钯基合金的出现；以及综合性能优越,尤其是抗有机气氛腐蚀性能良好的金基合金的出现。介绍了国外贵金属精密电阻合金专利概况、绕组／电刷材料合理的匹配关系。指出国际上创制新型贵金属精密电阻合金的物理冶金学手段不外乎是利用有序化、脱溶等固态转变、弥敞强化以及多组元化来获得优异的综合性能。文章分析讨论了对贵金属精密电阻合金有着重要意义的若干问题：接触电阻、耐磨性、摩擦系数与自润滑、选材与资源。文章最后指出目前我国水平同国际先进水平的差距和努力方向。上述五个基体的贵金属精密电阻合金的电学-机械性能集中分别列于表中。     

原位氧化对Al掺杂β-FeSi2热电材料结构与性能的影响

研究了快速凝固／热压Al掺杂FeSi2基合金中的微观组织特征以及原位生成氧化物颗粒对热电材料电学性能的影响。结果表明，随着对快速凝固粉末氧化处理时间的延长，P型掺杂的β-FeSi2半导体会先转变成n-型，然后又转变成P-型半导体，并存在“热伏极性反转”现象，氧化处理降低β-FeSi2基热电材料的电学性能，未经氧化处理的FeAl0.1Si2材料在测量温度范围内的功率因子最大，在500℃达到465μW.m^-1.K^-1。     

可穿戴热电发电器的研究进展

人体的能量大部分以热量的形式释放，其与外界的温差平均约5～30℃,因此体热可以很好地作为热电发电器的热源。与传统发电器相比，可穿戴热电发电器将人体所散发的低品位热量转化为有效电能，有可能为一些功率要求小于毫瓦级的无线传感器节点提供足够的能量，同时还具备无污染、轻便、稳定等特性，因此越来越受到关注。目前柔性可穿戴热电发电器的研究主要聚焦基于块体型热电材料、基于薄膜状型热电材料和基于纺织织物型热电材料的三大类热电发电器。其中，块体型热电发电器的输出功率一般为每平方厘米几十微瓦，热电臂材料主要为室温热电性能较高的碲化铋基合金，研究重点在于提升这类器件的输出性能和柔性。薄膜型热电发电器的输出功率一般在每平方厘米纳瓦和微瓦之间，按结构可分为水平型和垂直型，常见的水平型器件包含串联型、堆积与卷起型和折叠型，通常会产生较大的输出电压；而垂直型器件单位面积的热电臂对数增多，会产生较大的功率密度。纺织织物型热电发电器输出功率较小，但是具有优良的拉伸、弯曲和面内剪切性能，可以适应3D变形，更适合在弯曲的人体皮肤表面收集热量。本文综述了以上三大类主流的柔性可穿戴热电发电器的研究状况，并从设计、结构和性能方面...     

湿化学法制备纳米Bi2Te3基热电材料的研究进展

Bi2Te3基热电材料是室温下性能最好的热电材料。传统块体Bi2Te。基热电材料的热电性能不高,而纳米Bi2Tes基热电材料可以实现电、声输运特性的协同控制,从而提高材料的热电性能。介绍了几种纳米Bi2Te3。基热电材料不同的湿化学制备方法,比较了各种方法的优缺点,并展望了其发展方向。     

熵调控抑制ZrNiSn基half-Heusler热电材料的晶格热导率

ZrNiSn基half-Heusler热电材料具有较高的热导率, 限制了其热电性能进一步提高。为了降低晶格热导率, 本研究采用磁悬浮熔炼和放电等离子烧结的方法制备ZrNiSn和Zr_0.5Hf_0.5Ni_1-xPt_xSn (x=0, 0.1, 0.15, 0.2, 0.25, 0.3)高熵half-Heusler热电合金。在Zr位进行Hf原子替代, Ni位进行Pt原子替代以调控该合金的构型熵, 并研究构型熵对热电性能的影响。本工作优化了Zr_0.5Hf_0.5Ni_0.85Pt_0.15Sn在673 K的最小晶格热导率和双极扩散热导率之和为2.1 W·m^-1·K^-1, 与ZrNiSn相比降低了约58%。这一发现为降低ZrNiSn基合金的晶格热导率提供了一种有效的策略, 有助于改善材料的热电性能。     

湿化学法制备纳米Bi2Te3基热电材料的研究进展

Bi₂Te₃基热电材料是室温下性能最好的热电材料。传统块体Bi₂Te₃基热电材料的热电性能不高,而纳米Bi₂Te₃基热电材料可以实现电、声输运特性的协同控制,从而提高材料的热电性能。介绍了几种纳米Bi₂Te₃基热电材料不同的湿化学制备方法,比较了各种方法的优缺点,并展望了其发展方向。     

Ag2Q-Based (Q = S,Se, Te) Silver Chalcogenide Thermoelectric Materials

Thermoelectric technology provides a promising solution to sustainable energy utilization and scalable power supply. Recently, Ag₂Q-based (Q = S, Se, Te) silver chalcogenides have come forth as potential thermoelectric materials that are endowed with complex crystal structures, high carrier mobility coupled with low lattice thermal conductivity, and even exceptional plasticity. This review presents the latest advances in this material family, from binary compounds to ternary and quaternary alloys, covering the understanding of multi-scale structures and peculiar properties, the optimization of thermoelectric performance, and the rational design of new materials. The “composition-phase structure-thermoelectric/mechanical properties” correlation is emphasized. Flexible and hetero-shaped thermoelectric prototypes based on Ag₂Q materials are also demonstrated. Several key problems and challenges are put forward concerning further understanding and optimization of Ag₂Q-based thermoelectric chalcogenides.     

聚合物热电复合材料的研究进展

本文综述了碳纳米材料/聚合物、半导体合金/聚合物、金属纳米粒子/聚合物以及聚合物/聚合物等热电复合材料的研究进展。简要分析了热电复合材料的性能提升机理及现有材料尚存在的问题,并指出了聚合物热电复合材料今后的发展方向。     

SiGe:GaP合金的微观结构和温差电特性

经高温热处理后的 SiGe∶GaP 半导体温差电材料,其微观结构由具有富 Si 相特征变化成为具有富 Ge 相特征,温差电优值也得到了提高。实验还表明,材料晶格热导率的降低与富 Si 相的消失和富 Ge相的出现有关。然而,塞贝克系数和电导率的显著变化却与微观结构中富 Si 相和富 Ge 相的变化基本无关。通过对材料微观结构和温差电特性比较发现,具有富 Ge 相特征的微观结构对应于较大的温差电优值。     

Effects of electrically active point defects on the structure and electrical properties of Bi-Te-Se and Sb-Bi-Te solid solutions

The effects of intrinsic point defects on the electrical properties and structure ofp-type Sb-Bi-Te and n-type Bi-Te-Se alloys were studied. The concentrations of intrinsic donors and acceptors were shown to depend not only on the alloy composition but also on the self-compensation conditions in the materials doped with Group IV (Si, Ge, Sn, Pb) and VII (CI, I) elements. The Te-rich alloys doped with Cl or Pb to optimal carrier concentration show the best thermoelectric performance.     

Commercial ZrO2 paints as coatings for SiGe thermoelectric materials

The use of ZrO₂ paints to coat SiGe materials used in radioisotopic thermoelectric generators was studied. The best results were obtained when the SiGe alloys were double coated with a 200 h anneal at 1000° C after each coating. The thermoelectric properties of these coated samples were about the same as for the SiGe alloys coated by SiO₂ or Si₃N₄. The vapoursupression properties of the best ZrO₂ coatings fell between those of SiO₂ and Si₃N₄. In the SiGe doped with GaP alloys, the interface between the oxide coating and alloy is enriched with Ga₂O₃.     

Thermoelectric properties of BiSb alloys

Bismuth is a semimetal that has a relatively low lattice thermal conductivity. A positive energy gap can be created by alloying with antimony, leading to useful alloys for thermoelectric energy conversion. This paper gives an insight into the basic properties of BiSb alloys for thermoelectric applications.     

Stability,magnetic, electronic,elastic, thermodynamic,optical, and thermoelectric properties of Co2TiSn,Co2ZrSn and Co2HfSn Heusler alloys from calculations using generalized gradient approximation techniques

Structural, magnetic, electronic, elastic, thermodynamic, optical, and thermoelectric properties of full-Heusler alloys Co₂YSn (Y?=?Ti; Zr; Hf) were determined using density functional theory-based WIEN2k code within GGA and GGA?+?U approximations for exchange correlation functions. The calculated formation energies and elastic parameters demonstrate the stability of these alloys. It was also observed that the studied compounds have a ductile structure and exhibit anisotropic behavior. The magnetic moment of these systems is equal to 2 μ_B, which conforms to the Slater–Pauling rule. In addition, the half-metallic ferrimagnetic behavior and good bandgap in the minority spin are showed for all compounds. The optical properties are systematically studied by computing the optical parameters. The existence of bandgaps with minimal energy loss in IR and visible regions makes these materials suitable candidates for optoelectronic devices. The thermoelectric properties of these systems were also examined in terms of temperature and chemical potential.

     

Extruded thermoelectric materials based on Bi<Subscript>2</Subscript>Te<Subscript>3</Subscript>-Bi<Subscript>2</Subscript>Se<Subscript>3</Subscript> solid solutions

Extruded n-type materials based on Bi₂Te₃-Bi₂Se₃ alloys containing 6 to 40 mol % Bi₂Se₃ have been investigated using microstructural analysis and thermoelectric measurements at room temperature and in the range 100–400 K. Their electrical properties have been compared to those of single-crystal analogs. Compositions have been found at which the extruded materials offer the highest thermoelectric performance in different temperature ranges.     

低维Bi_2Te_3基热电材料的研究进展

Bi_2Te_3及其固溶体金金是目前室温附近发展最为成熟、性能最好的一类热电材料,在热电制冷及温差发电方面具有广阔的应用前景.如何最大限度地提高材料的热电优值是当今热电材料研究的主要问题.传统块体Bi_2Te_3基热电材料的最高ZT值只能达到1.0左右,而低维化、纳米化的Bi_2Te_3基热电材料可使电子和声子的传输得到合理调控,从而大幅提升材料的热电性能.综述了二维纳米薄膜、一维纳米线(管、棒)和准零维纳米颗粒等低维Bi_2Te_3基热电材料的最新研究进展,并结合目前的研究状况展望了今后的研究重点及发展方向.     

聚3, 4-乙烯二氧噻吩: 聚苯乙烯磺酸盐基柔性复合热电材料研究进展

热电材料可以实现热能与电能的直接转化,是一种安全环保的新型能源材料。近年来,随着可穿戴电子设备的发展,柔性热电材料成为研究人员关注的焦点。传统无机热电材料具有优异的热电性能,但由于自身固有的脆性,限制了在柔性领域的发展。聚3, 4-乙烯二氧噻吩: 聚苯乙烯磺酸盐(PEDOT: PSS)具有高电导率、低热导率和良好的柔性,在柔性热电领域具有巨大的潜力。当选择合适的无机填料与PEDOT: PSS进行复合,可以得到优异的热电性能和良好的力学性能。本文综述了PEDOT: PSS基纳米复合薄膜的最新进展,并详细介绍了提高PEDOT: PSS基纳米复合薄膜热电性能的有效方法。最后,本文总结了实现高性能PEDOT: PSS基柔性热电材料的途径及面对的挑战。