Compliant and stretchable thermoelectric coils for energy harvesting in miniature flexible devices

Nan, Kewang; Kang, Stephen Dongmin; Li, Kan; Yu, Ki Jun; Zhu, Feng; Wang, Juntong; Dunn, Alison C.; Zhou, Chaoqun; Xie, Zhaoqian; Agne, Matthias T.; Wang, Heling; Luan, Haiwen; Zhang, Yihui; Huang, Yonggang; Snyder, G. Jeffrey; Rogers, John A.

doi:10.1126/sciadv.aau5849

Cited by 215 publications

(190 citation statements)

References 49 publications

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“… 4)Matching thermal resistances between heat sources and FTE devices, as well as overcoming the mechanical inflexibility of inorganic TE legs via microfabrication. In order to match heat sources, the thermal resistance of FTE devices can be adjusted by optimizing device dimensions and geometry, where finite element analysis could be effective in predicting corresponding thermal resistances . By combining microscale inorganic TE legs into flexible substrates, microfabrication might be an effective way to overcome the mechanical inflexibility of inorganic TEs .…”

Section: Discussionmentioning

confidence: 99%

Flexible Thermoelectric Materials and Generators: Challenges and Innovations

et al. 2019

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The urgent need for ecofriendly, stable, long‐lifetime power sources is driving the booming market for miniaturized and integrated electronics, including wearable and medical implantable devices. Flexible thermoelectric materials and devices are receiving increasing attention, due to their capability to convert heat into electricity directly by conformably attaching them onto heat sources. Polymer‐based flexible thermoelectric materials are particularly fascinating because of their intrinsic flexibility, affordability, and low toxicity. There are other promising alternatives including inorganic‐based flexible thermoelectrics that have high energy‐conversion efficiency, large power output, and stability at relatively high temperature. Herein, the state‐of‐the‐art in the development of flexible thermoelectric materials and devices is summarized, including exploring the fundamentals behind the performance of flexible thermoelectric materials and devices by relating materials chemistry and physics to properties. By taking insights from carrier and phonon transport, the limitations of high‐performance flexible thermoelectric materials and the underlying mechanisms associated with each optimization strategy are highlighted. Finally, the remaining challenges in flexible thermoelectric materials are discussed in conclusion, and suggestions and a framework to guide future development are provided, which may pave the way for a bright future for flexible thermoelectric devices in the energy market.

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Section: Discussionmentioning

confidence: 99%

Flexible Thermoelectric Materials and Generators: Challenges and Innovations

et al. 2019

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“…The performance of TEGs can be defined by the high thermoelectric figure‐of‐merit ZT = S 2 σT /κ, where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the thermal conductivity, and T is the absolute temperature . Inorganic materials, such as metal chalcogenides or oxides, carbon, the half‐Heusler compound, Bi–Te alloys, skutterudite compounds, and metal silicides, were commonly used TMs . The highest ZT value based on the inorganic TMs reported by Zhao et al was around 2.6 at 923 K, which was realized in the SnSe single crystal .…”

Section: Materials For Energy Conversion Devicesmentioning

confidence: 99%

Fiber‐Based Energy Conversion Devices for Human‐Body Energy Harvesting

et al. 2019

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body is actually a tremendous storehouse of energy that is generated from body heat and motion. [15][16][17][18][19] Power generation from breathing, heating, blood transport, arm motion, typing, and walking could reach to over 100 W for a 68 kg adult's daily activities (Figure 1). [20] Thus, converting 1% of power from the human body may be enough to support the work of most portable electronics.In the past two decades, researchers have developed several energy conversion devices based on piezoelectricity, electrostaticity, triboelectricity, or thermoelectricity that can directly harvest the mechanical or thermal energy and convert it into electric energy (these conversion devices are so-called nanogenerators (NGs)). [21][22][23][24][25] The first nanogenerator (NG) based on ZnO was invented by Prof. Wang in 2006; after that, various NGs were developed to harvest the mechanical or thermal energy with the output performance increasing gradually. [26] These NGs are easy-to-construct flexible devices since most materials for these devices are polymers and nanomaterials. Generally, the flexible devices assembled by film materials can be stretchable and bendable in one direction. But their lack of air-permeability, poor 3D deformation, and low damage tolerance limit their application, especially for wearable electronics. Therefore, fiberbased energy conversion devices have been designed. [27] These fiber-based devices can also be knitted to yarn or fabric in the clothing system to build up a large area electronic system. [28,29] The energy generation and internal charging can be realized by means of a self-powered system that harvests the energy from natural sources around the human body to sustain the wearable electronics. [30][31][32] The search for functional materials that possess good conversion efficiency, as well as great mechanical and environmental stability, combined with a novel device design might push these devices to meet the requirement of a practical application. In the past decade, numerous contributions have been offered to improve the performance of fiber-based energy conversion devices (FBECD) and extend its application. This review specifically summarizes FBECD with different energy conversion mechanisms including piezoelectricity, electrostaticity, triboelectricity, and thermoelectricity in recent processes (Figure 2). The functional materials, fiber fabrication techniques, and device design strategies for different classes of FBECDs are covered in the article. We also introduce an overview of the fiber-based self-powered system and sensors and Following the rapid development of lightweight and flexible smart electronic products, providing energy for these electronics has become a hot research topic. The human body produces considerable mechanical and thermal energy during daily activities, which could be used to power most wearable electronics. In this context, fiber-based energy conversion devices (FBECD) are proposed as candidates for effective conversion of human-body energy into electricity...

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“…However, this device configuration is not suitable for thermoelectric 2D materials on flexible substrates since the bending direction is vertical to the 2D material film. Very recently, a groundbreaking architectural solution was demonstrated by Nan in 2018 . Figure c shows a schematic illustration of the process of fabricating 3D thermoelectric modules based on 2D thermoelectric materials on flexible films.…”

Section: Future Perspectivesmentioning

confidence: 99%

“…Following the release of the prestretch, geometrical transformation starts to yield the final 3D architectures. Reproduced with permission . Copyright 2018, American Association for the Advancement of Science.…”

Section: Future Perspectivesmentioning

confidence: 99%

2D Materials for Large‐Area Flexible Thermoelectric Devices

Kanahashi

Takenobu

2019

Advanced Energy Materials

158

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The rapid development of the concept of the “Internet of Things (IoT)” requires wearable devices with maintenance‐free batteries, and thermoelectric energy conversion based on large‐area flexible materials has attracted much attention. Among large‐area flexible materials, 2D materials, such as graphene and related materials, are promising for thermoelectric applications due to their excellent transport properties and large power factors. In this Review, both single‐crystalline and polycrystalline 2D materials are surveyed using the experimental reports on thermoelectric devices of graphene, black phosphorus, transition metal dichalcogenides, and other 2D materials. In particular, their carrier‐density dependent thermoelectric properties and power factors maximized by Fermi level tuning techniques are focused. The comparison of the relevant performances between 2D materials and commonly used thermoelectric materials reveals the significantly enhanced power factors in 2D materials. Moreover, the current progress in thermoelectric module applications using large‐area 2D material thin films is summarized, which consequently offers great potential for the use of 2D materials in large‐area flexible thermoelectric device applications. Finally, important remaining issues and future perspectives, such as preparation methods, thermal transports, device designs, and promising effects in 2D materials, are discussed.

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Compliant and stretchable thermoelectric coils for energy harvesting in miniature flexible devices

Abstract: Thermoelectric coils for energy harvesting are fabricated in miniature flexible devices.

Cited by 215 publications

References 49 publications

Flexible Thermoelectric Materials and Generators: Challenges and Innovations

Flexible Thermoelectric Materials and Generators: Challenges and Innovations

Fiber‐Based Energy Conversion Devices for Human‐Body Energy Harvesting

2D Materials for Large‐Area Flexible Thermoelectric Devices

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