Synthesis and Thermoelectric Property of 1D Flexible PEDOT: p-TSA/Glass Fiber

Exploiting the thermal insulation properties of glass fiber and excellent conductivity of conducting polymer, a novel one-dimensional (1D) composite thermoelectric material, based on poly(3,4-ethylenedioxythiophene): p-toluenesulfonic acid (PEDOT: p-TSA)/glass fiber, is prepared by coating the PEDOT: p-TSA on the surface of glass fiber with in situ polymerization method. We hope the materials can bring out the performance of the “electron conductor, photon glass”. During the polymerization process, the effects of oxidant concentration and dopant mass fraction on thermoelectric properties of the materials are investigated. The group type of the polymer chain and the morphology of the samples were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), respectively. The maximal Seebeck coefficient (S) and electric conductivity (σ) of the pristine sample are 32 μVK-1 and 169 Sm-1, respectively. After further post-processing with methanol, the thermoelectric properties of materials were improved, and the maximum value of S and σ increased greatly to 48.5 μVK-1 and 3184 Sm-1, respectively. The maximal power factor (PF) of materials also increased from 0.12 μWm-1 K-2 to 6.74 μWm-1 K-2. Moreover, we have proposed a preliminary explanation on the carrier transport mechanism.

Permeable carbon fiber based thermoelectric film with exceptional EMI shielding performance and sensor capabilities

Thermoelectric(TE)technologies offer a promising approach for directly converting skin heat into electricity for wearable electronics.Recognizing p-type Sb2Tes and n-type BizTes as top-performing materials at room temperature,their rigid inorganic structure,with ultralow moisture permeability,poses challenges in warm and humid conditions,fostering bacterial growth and potential skin issues.To address this issue,we developed a cross-linked core-shell structure by electrodepositing Sb_(2)Te_(3)(Bi_(2)Te_(3))onto carbon fiber(CF).This architecture significantly improved the electrical conductivity and the Seebeck coefficient,resulting in a remarkable 300-fold increase in the power factor compared to that of pure CF.The CF/Sb_(2)Te_(3) and CF/Bi2Te films demonstrated optimal power factors of 450 and 121μW·m^(-1)·K^(-2),respectively.Moreover,the fabricated films exhibited outstanding moisture permeability,over 3000 g·m^(-2)·d^(-1),exceptional electromagnetic interference shielding efficiency approaching 93 dB,and versatility as sensors for language assistance and respiratory monitoring.These attributes underline their broad applicability,emphasizing their suitability for human health protection in diverse scenarios.

Highly flexible and excellent performance continuous carbon nanotube fibrous thermoelectric modules for diversified applications

A highly flexible and continuous fibrous thermoelectric(TE)module with high-performance has been fabricated based on an ultra-long single-walled carbon nanotube fiber,which effectively avoids the drawbacks of traditional inorganic TE based modules.The maximum output power density of a 1-cm long fibrous TE module with 8 p–n pairs can reach to 3436μW·cm^(-2),the power per unit weight to 2034μW·g^(-1),at a steady-state temperature difference of 50 K.The continuous fibrous TE module is used to detect temperature change of a single point,which exhibits a good responsiveness and excellent stability.Because of its adjustability in length,the flexible fibrous TE module can satisfy the transformation of the temperature difference between two distant heat sources into electrical energy.Based on the signal of the as-fabricated TE module,a multi-region recognizer has been designed and demonstrated.The highly flexible and continuous fibrous TE module with excellent performance shows a great potential in diversified applications of TE generation,temperature detection,and position identification.

Temperature‑Arousing Self‑Powered Fire Warning E‑Textile Based on p-n Segment Coaxial Aerogel Fibers for Active Fire Protection in Firefighting Clothing

Firefighting protective clothing is a crucial protective equipment for firefighters to minimize skin burn and ensure safety firefighting operation and rescue mission.A recent increasing concern is to develop self-powered fire warning materials that can be incorporated into the firefighting clothing to achieve active fire protection for firefighters before the protective clothing catches fire on fireground.However,it is still a challenge to facilely design and manufacture thermoelectric(TE)textile(TET)-based fire warning electronics with dynamic surface conformability and breathability.Here,we develop an alternate coaxial wet-spinning strategy to continuously produce alternating p/n-type TE aerogel fibers involving n-type Ti_(3)C_(2)T_(x)MXene and p-type MXene/SWCNT-COOH as core materials,and tough aramid nanofiber as protective shell,which simultaneously ensure the flexibility and high-efficiency TE power generation.With such alternating p/n-type TE fibers,TET-based self-powered fire warning sensors with high mechanical stability and wearability are successfully fabricated through stitching the alternating p-n segment TE fibers into aramid fabric.The results indicate that TET-based fire warning electronics containing 50 p-n pairs produce the open-circuit voltage of 7.5 mV with a power density of 119.79 nW cm-2 at a temperature difference of 300℃.The output voltage signal is then calculated as corresponding surface temperature of firefighting clothing based on a linear relationship between TE voltage and temperature.The fire alarm response time and flame-retardant properties are further displayed.Such self-powered fire warning electronics are true textiles that offer breathability and compatibility with body movement,demonstrating their potential application in firefighting clothing.

Optimization of the Thermoelectric Performances of CoSbS Semiconductors Using the High-Pressure Fabrication Method

CoSbS-based compounds are good thermoelectric materials with low thermal conductivity and good electrical properties,which can effectively be used to improve the efficiency of many thermoelectric conversion processes.In order to improve their properties even more,in this study a series of experiments have been conducted in the frame of the traditional solid-phase synthesis and high-pressure method.It is shown that if the mass fluctuation and stress fluctuation in the considered CoSbS system increase,the scattering probability of phonons is enhanced and the lattice thermal conductivity of the material is reduced.Adding a small amount of Se can simultaneously optimize three thermoelectric properties,i.e.,the Seebeck coefficient is improved,the thermal conductivity becomes smaller and the quality factor grows.At the same time,the thermal and electrical properties of bulk materials can be optimized by using nano-scale Ni doped CoSbS samples.As shown by the experiments,Nidoped Co sites can effectively improve the carrier concentration,the effective mass of the density of states of the material,and the power factor.Under the same temperature conditions,the thermoelectric figure of merit(ZT)of Co1−yNiySbS1−xSex synthesized under high pressure,at x=0.15,y=0.1 is much higher than the corresponding value for CoSbS prepared by traditional methods.

柔性电子材料在可穿戴设备中的研究进展

在电子技术与现代纺织技术融合的背景下,更加柔性、传输信号更加灵敏精准、监控范围更加广泛的可穿戴设备成为研究热点,为此,研究人员着力于开发新型柔性电子材料。文章简要总结了可穿戴设备中所用新型柔性电子材料的研究进展,重点介绍了柔性传感材料、导电材料、供电材料的研究现状及发展方向,同时指出了目前柔性电子材料在制备过程及成品性能方面存在的不足及未来研究趋势。

应用于光纤传感网络的热电发生器设计与研究

研制并测试了用于光纤海底地震传感网络节点的热电能量收集系统。基于碲化铋热电材料,制作了用于光纤传感器的热电发生器(TEG),建立了热电模型并进行了验证。提出了一种将TEG输出的能量收集并利用的能量管理电路。详细介绍了该系统的设计思想、电路原理图和模拟水下环境实验。实验数据表明:所制作的TEG能够以2.67%的效率将热能直接转换成电能,设计的能量管理电路能够以23.09%的效率将电能收集并利用。该研究结果对延长光纤海底节点工作时间、增加系统可靠性有重要意义。

碳纳米管纤维基热电器件的制备及其性能研究

利用温差发电的柔性热电器件具有可持续、环保和可穿戴的优点,但是多数热电器件需要利用金属电极相互连接,这在一定程度上降低了热电器件的整体性能。本文利用OA和FeCl 3对碳纳米管纤维进行N型和P型掺杂,制备了无需金属电极连接的具有连续P-N结构的热电纤维,并且利用热电纤维制备了3D热电器件。结果显示,N型和P型碳纳米管纤维基热电纤维分别具有-69.7、62.2μV K的高塞贝克系数和552.9、431.4μW(m·K 2)的高功率因数,3D热电器件能够利用人体与环境之间垂直方向上的温差产生开路电压,并可用作简单的温度传感器。这种3D热电器件具有优异的热电性能,在柔性自供电领域有广泛的应用前景。

可穿戴纤维基能源转换器件研究进展

随着智能可穿戴设备的普及,其能源供应问题愈加突出,一种绿色且高效的供能系统有待被研发。纤维基能源转换器件凭借着其优异的可集成性和宏观可调性,在柔性穿戴领域受到了越来越多的关注,有望成为解决新一代能源供给问题的有效方案。为进一步深化对纤维基能源转换方案的认识,本文主要回顾了压电、热电和磁电纤维基能源转换器件的最新研究与应用进展,重点讨论了压电纤维、热电纤维和磁电纤维的制备方法、性能分析和可穿戴应用,最后提出了纤维基能源转换器件在应用中所面临的问题与挑战,并对其未来的发展趋势进行了展望。

Bi_(2)Te_(3)/KOH/PEDOT:PSS和SiO_(2)气凝胶增强钢丝绒热电性能研究

在热电材料研究领域,一般认为金属的Seebeck系数较低,因此有关金属的热电性能的研究并不多见。但研究发现金属的物理形态对其热电性能具有影响。考察了金属纤维钢丝绒(SW)的热电性能。发现SW(主要成分为Fe)的Seebeck系数是块体铁的2倍。在此基础上,将SW与有机和无机热电材料进行复合,并在其空隙中填充SiO_(2)气凝胶,最终制备出了Bi_(2)Te_(3)/KOH/PEDOT:PSS@SW-SiO_(2)气凝胶复合材料,使其热电性能得到了进一步提升。结果表明,气凝胶的加入可使SW的导热系数降低34%。电导率(σ)、热导率(κ)和Seebeck系数(S)得到解耦。Bi_(2)Te_(3)/KOH/PEDOT:PSS@SW-SiO_(2)气凝胶的Seebeck系数、热电优值(ZT)和功率因子(PF)分别是纯SW的1.2、3.4、2.4倍。通过改变材料物理形态和添加气凝胶来提高材料热电性能的方式有望为其他热电材料的研究提供新的思路和有益参考。

碳纤维增强复合材料层压板的雷击烧蚀损伤及剩余强度分析

轻质高强的碳纤维增强复合材料(CFRP)已广泛应用于飞机结构中,但是相较于金属而言其导电性能较弱,因此必须考虑雷击的影响。由于雷电流分量C波通常对CFRP造成的损伤最为严重,因此本文建立了C波的热电耦合模型和CFRP层压板的有限元模型,模拟CFRP层压板在C波作用下的雷击损伤。雷击后,CFRP层压板内部在室温下存在热辐射和热传导,会使得损伤进一步扩展。基于扩展后的损伤,使用Hashin准则进行失效判定,预测了CFRP层压板的剩余压缩强度。

Review on Fiber-Based Thermoelectrics:Materials,Devices,and Textiles

With the development and prosperity of Internet of Things(IoT)technology,wearable electronics have brought fresh changes to our lives.The demands for low power consumption and mini-type wearable power systems for wearable electronics are more urgent than ever.Thermoelectric materials can efficiently convert the temperature difference between body and environment into electrical energy without the need for mechanical components,making them one of the ideal candidates for wearable power systems.In recent years,a variety of high-performance thermoelectric materials and processes for the preparation of large-scale single-fiber devices have emerged,driving the application of flexible fiber-based thermoelectric generators.By weaving thermoelectric fibers into a textile that conforms to human skin,it can achieve stable operation for long periods even when the human body is in motion.In this review,the complete process from thermoelectric materials to single-fiber/yarn devices to thermoelectric textiles is introduced comprehensively.Strategies for enhancing thermoelectric performance,processing techniques for fiber devices,and the wide applications of thermoelectric textiles are summarized.In addition,the challenges of ductile thermoelectric materials,system integration,and specifications are discussed,and the relevant developments in this field are prospected.

Mechanical Properties of Submicron Glass Fiber Reinforced Vinyl Ester Composite

Vinyl ester (VE) resin inherently has intrinsic brittleness due to its high cross-link density. To improve mechanical performance, micro/nano fillers are widely used to modify this matrix. In present study, glass fiber in submicron scale at low contents was added into VE to prepare submicron composite (sMC). The impact resistance of un-notched sMC degraded with the increase of sGF content while that of notched-sMC remained the unchanged. Flexural properties of sMCs also were the same with that of neat resin. The results of Dynamic mechanical analysis (DMA) test showed the slight increase of storage modulus and the decrease of tan delta value in the case of sMC compared to those of un-filled matrix. However, the Mode I fracture toughness of sMC improved up to 26% and 61% corresponding to 0.3 and 0.6 wt% glass fiber used. The compact tension sample test suggests that there is the delay of crack propagation under tensile cyclic load in resin reinforced by submicron glass fiber. The number of failure cycle enlarged proportionally with the increment of sGF content in matrix.

先进功能材料钎焊连接研究进展

以复相陶瓷、纤维增强陶瓷基复合材料以及热电材料为例,从钎料成分设计、钎缝界面组织调控、接头残余应力缓解以及钎焊接头性能评测等角度,讨论了近年来发表的研究成果。结果表明,在钎料中添加活性元素以及对母材表面改性的方法,能够有效改善钎料润湿性和界面结合强度;对于界面元素扩散以及母材过渡溶解的问题,可以设计制备复合钎料或阻隔层进行解决;接头残余应力的大小受材料热膨胀系数差异的影响较大,目前已提出了多孔中间层、梯度复合层以及母材表面机械加工等多种创新方法,但研究成果的应用仍停留在小尺寸样件,对于缓解大尺寸接头的残余应力问题仍有待解决。最后对相关研究方向进行了总结和展望,期望推动航空航天构件连接的发展进程。

Systematic characterization of transport and thermoelectric properties of a macroscopic graphene fiber

Graphene, a two-dimensional material with extraordinary electrical, thermal, and elastic performance, is a potential candidate for future technologies. However, the superior properties of graphene have not yet been realized for graphenederived macroscopic structures such as graphene fibers. In this study, we systematically investigated the temperature （T ）-dependent transport and thermoelectric properties of graphene fiber, including the thermal conductivity （A）, electrical conductivity （o）, and Seebeck coefficient （S）. A increases from 45.8 to 149.7 W·m^-1·K^-1 and then decreases as T increases from 80 to 290 K, indicating the boundary-scattering and three-phonon Umklapp scattering processes. σ increases with T from 7.1 × 10^4 to 1.18 × 10^5 S·m^-1, which can be best explained by the hopping mechanism. S ranges from -3.9 to 0.8 μV·K^-1 and undergoes a sign transition at approximately 100 K.

Chemically doped macroscopic graphene fibers with significantly enhanced thermoelectric properties

Flexible wearable electronics, when combined with outstanding thermoelectric properties, are promising candidates for future energy harvesting systems. Graphene and its macroscopic assemblies （e.g., graphene-based fibers and films） have thus been the subject of numerous studies because of their extraordinary electrical and mechanical properties. However, these assemblies have not been considered suitable for thermoelectric applications owing to their high intrinsic thermal conductivity. In this study, bromine doping is demonstrated to be an effective method for significantly enhancing the thermoelectric properties of graphene fibers. Doping enhances phonon scattering due to the increased defects and thus decreases the thermal conductivity, while the electrical conductivity and Seebeck coefficient are increased by the Fermi level downshift. As a result, the maximum figure of merit is 2.76 ~ 10~, which is approximately four orders of magnitude larger than that of the undoped fibers throughout the temperature range. Moreover, the room temperature power factor is shown to increase up to 624 btW.m-l.K-2, which is higher than that of any other material solely composed of carbon nanotubes and graphene. The enhanced thermoelectric properties indicate the promising potential for graphene fibers in wearable energy harvesting systems.

Fibrous Separator with Surface Modification and Micro-Nano Fibers Lamination Enabling Fast Ion Transport for Lithium-Ion Batteries

Appropriate materials collaborated with reasonable structure can significantly increase the separator performance for lithium-ion batteries.In this work,taking the advantages of microfibrous and nanofibrous membranes and compensating for their defects,we developed a composited separator(GOPPH)with excellent overall performance by first wetting-modifying the polyethylene terephthalate microfibers and then laminating a polyvinylidene fluoride-hexafluoropropylene nanofiber layer.Such a combination not only offers the GOPPH separator,from the perspective of structure,with high porosity and hierarchical structure in terms of fiber diameter and pore size,but also provides satisfactory features including wettability,mechanical strength and thermal shutdown function that benefit from the selected materials.Meanwhile,as determined by experimental and theoretical approaches,the obtained GOPPH separator exhibits considerably enhanced lithium ion transport ability with a high lithium ion transference number and transport rate,which thereby endowing the cell with superior cycling stability with a capacity retention of 93%after 200 cycles at 1 C.Therefore,considering battery safety and performance,the GOPPH fibrous membrane could be a promising separator candidate for lithium-ion batteries.

聚乙烯醇对PEDOT:PSS纤维热电性能和拉伸性能的协同增强

聚(3,4-乙烯二氧噻吩):聚苯乙烯磺酸盐(PEDOT:PSS)纤维通常通过湿法纺丝制得,但其电导率较低,且拉伸性较差,限制了其在可穿戴热电器件中的应用。为提升PEDOT:PSS纤维的导电和拉伸性能,通过在PEDOT:PSS溶液中加入不同质量分数的聚乙烯醇(PVA)制备PEDOT:PSS/PVA复合纤维,研究其导电性能、热电性能和拉伸性能。结果表明,PVA的加入可显著提升复合纤维的导电性,但其塞贝克系数未发生明显变化。当ω(PVA)为9.1%时,复合纤维的电导率最高,可达到257.3 S/cm,其热电功率因子为8.27μW/(m·K^(2))。同时,复合纤维的断裂伸长率随ω(PVA)增加而增加,而抗拉强度随ω(PVA)增加先增加后减小,在ω(PVA)为33.3%时达到最高。研究表明,PVA可协同增强PEDOT:PSS纤维的热电性能和拉伸性能,在柔性可穿戴设备和智能织物等领域具有较大的应用潜力。

Tailoring microstructure and electrical transportation through tensile stress in Bi_(2)Te_(3) thermoelectric fibers

Bismuth telluride(Bi_(2)Te_(3))has attracted much attention in the field of thermoelectrics since it is one kind of commercial room-temperature thermoelectric material.Herein three kinds of Bi_(2)Te_(3) thermoelectric fibers with internal tensile stress are fabricated utilizing an optical fiber template method.The effects of internal stress on the microstructure and the electrical transportation of Bi_(2)Te_(3) thermoelectric fibers are investigated.The Bi_(2)Te_(3) cores in the fibers are highly crystalline and possess a tensile nanosheet structure with preferential orientation as evidenced by X-ray diffraction and Raman studies.Tensile stress can enhance electrical properties of the fibers.And a paper cup generator covered with 20 pieces of optimized fibers provides a μW-level output power.It is inferred that tensile stress tuning can be an effective tool for the material optimization of thermoelectric performance.

碳纳米管-碳纤维/水泥基材料微观结构和热电性能

研究了碳纳米管-碳纤维/水泥基材料的微观结构以及碳纳米管-碳纤维/水泥基材料升温与降温过程中的热电性能。实验结果表明,当水泥基材料中碳纳米管掺量较低时(碳纳米管掺量占水泥质量百分比不高于0.5%),碳纳米管能有效改善水泥基体性能,密实基体结构。在碳纤维水泥基材料中掺入碳纳米管能有效提高和改善复合材料热电性能;当碳纳米管掺量为水泥质量0.5%,水泥基材料热电势率最多能提高260%,达到22.6μV/℃。与此同时,碳纳米管掺入能增强热电效应中温差电动势与温差关系的线性规律和可逆性规律。