Thermoelectric Micro / Nano Generators, Volume 1 E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 383

Veröffentlichungsjahr: 2023

Beschreibung

This book explores a key technology regarding the importance of connections via an Internet of Things network and how this helps us to easily communicate with others and gather information. Namely, what would happen if this suddenly became unavailable due to a shortage of power or electricity? Using thermoelectric generators is a viable solution as they use the heat around us to generate the much-needed electricity for our technological needs. This first volume explores the computational and data-driven development of these thermoelectric generators, as well as the use of various abundant materials such as copper and silver chalcogenides and nanocarbons. It also offers reviews on universal property enhancement principles and the case of strongly correlated oxides, and goes on to explore the metrology of the thermal properties of thermoelectric generators, detailing methods of how to measure the absolute Seebeck coefficient using the Thomson effect and the thermal diffusivity of thin films using the ultrafast laser flash method.

Leseprobe

SCIENCES

Energy, Field Directors – Alain Dollet and Pascal Brault

Energy Recovery, Subject Head – Gustavo Ardila

Thermoelectric Micro/Nano Generators 1

Fundamental Physics, Materials and Measurements

Coordinated by

Hiroyuki AkinagaAtsuko KosugaTakao MoriGustavo Ardila

First published 2023 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:

ISTE Ltd27-37 St George’s RoadLondon SW19 4EUUKwww.iste.co.uk

John Wiley & Sons, Inc.111 River StreetHoboken, NJ 07030USAwww.wiley.com

© ISTE Ltd 2023The rights of Hiroyuki Akinaga, Atsuko Kosuga, Takao Mori and Gustavo Ardila to be identified as the authors of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s), contributor(s) or editor(s) and do not necessarily reflect the views of ISTE Group.

Library of Congress Control Number: 2023942071

British Library Cataloguing-in-Publication DataA CIP record for this book is available from the British LibraryISBN 978-1-78945-144-3

ERC code:PE8 Products and Processes Engineering PE8_6 Energy processes engineering

Preface

Hiroyuki AKINAGA1, Atsuko KOSUGA2 and Takao MORI3,4

1National Institute of Advanced Industrial Science and Technology (AIST), Device Technology Research Institute, Japan

2Osaka Metropolitan University, Department of Physical Science, Graduate School of Science, Japan

3National Institute for Materials Science (NIMS), WPI-MANA, Japan

4Graduate School of Pure and Applied Sciences, University of Tsukuba, Japan

Utilizing the Seebeck effect, thermoelectric materials can convert heat into electricity with a solid state device, i.e. a thermoelectric generator. This has the potential to contribute largely to society, considering around half of all primary energy consumed, i.e. fossil fuels, are lost in the form of waste heat, and the viable application of thermoelectric generators can lead to substantial energy saving. Furthermore, the trillions of sensors necessary for the Internet of Things (IoT) need a dynamic, maintenance-free power source of which thermoelectric generators are a promising candidate. The latter application is attractive because the motivation is not to supply cheap electricity, but high value electricity, which is suited for thermoelectrics, and also because thermoelectric conversion is viable with small size devices. With this background in mind, this two volume edition of Thermoelectric Micro/Nano Generators has been produced to serve as an important, comprehensive set of books, encompassing the fundamental principles, state-of-the-art advancements and outlooks for this topic.

In Volume 1, we mainly deal with fundamental physics, materials and measurements. After an introduction on the Strategies for Development of High Performance Thermoelectric Materials (Chapter 1) by several of the editors, a comprehensive chapter on Computational and Data-Driven Development of Thermoelectric Materials (Chapter 2) is given by Prashun Gorai and Michael Toriyama. They present in detail the general theory of carrier and phonon transport, also including defect formation and doping, which are powerful tools for thermoelectric enhancement. Recent powerful advancements in the computation field have been made regarding materials informatics and machine learning. The authors give detailed advice on how to use machine learning to accelerate the search for promising thermoelectric materials.

The next four chapters cover the detailed development and outlook of several promising thermoelecric material systems. Notable traditional high performance thermoelectric materials systems include Bi2Te3 and PbTe, which have unattractive features such as the extreme rareness of Te and high toxicity of Pb. Four more sustainable material systems are presented. Holger Kleinke covers Thermoelectric Copper and Silver Chalcogenides (Chapter 3). Cu2S, Cu2Se and their silver counterparts are abundant materials which have been reported to exhibit an extremely high number of merits. This chapter covers their basic features and recent advancements, also regarding their stability, which has been an issue, together with developments of several other selected chalcogenides. Michihiro Ohta, Priyanka Jood and Kazuki Imasato have provided a comprehensive chapter on Sulfide Thermoelectrics: Materials and Modules (Chapter 4). The versatility and high performance of a wide variety of sulfide materials, from layered sulfides like TiS2-based compounds and misfit compounds, high temperature rare earth sulfides, Chevrel-phase sulfides and mineral-based sulfides, such as tetrahedrite, colusite, chalcopyrite, etc., and module fabrication and performance of some of the compounds, are covered. Ichiro Terasaki has provided A Concise Review of Strongly Correlated Oxides (Chapter 5). Oxides are some of the most inexpensive, stable and abundant compounds. Terasaki particularly focuses on the physics principles; namely the strong correlation and manifestation of the spin and orbital degrees of freedom in the thermoelectric properties, which have resulted in notable high performances. He systematically covers several intriguing systems in the 3D transition-metal oxides and 4D transition-metal oxides, while giving the wide context and meaning in terms of physical principles. Tsuyohiko Fujigaya and Yoshiyuki Nonoguchi cover the relatively recent emergence of Nanocarbon Materials as Thermoelectric Generators (Chapter 6). They particularly focus on the fundamentals and development of thermoelectric carbon nanotubes (CNTs). The production capability and quality control of CNT materials has advanced significantly to make it a candidate for one of the potentially most abundant and sustainable material families. The authors review in detail the thermoelectric properties of CNTs and control via doping, and also comprehensively cover the utilization of CNTs in various format thermoelectric generators, including details of processing such as via ink, etc.

The final two chapters deal with the metrology of thermal properties. Precise evaluation of the thermoelectric properties is critical for the effective development of materials and devices. Yasutaka Amagai covers the Precise Measurement of the Absolute Seebeck Coefficient from the Thomson Effect (Chapter 7). He includes an instructive and detailed introduction to the measurement principles of the Seebeck coefficent, and elucidates new methods regarding precision measurement of the absolute Seebeck coefficient, which is also known as the absolute scale of thermoelectricity. Tetsuya Baba, Takahiro Baba and Takao Mori have provided a chapter on Thermal Diffusivity Measurement of Thin Films by Ultrafast Laser Flash Method (Chapter 8). The accurate evaluation of thermal diffusivity, and thereby thermal conductivity of thin films, is a difficult topic, which is important not just for thermoelectrics, but for a variety of fields. The principles of the measurement of bulk materials is given, and advances in the ultrafast laser flash method utilizing thermoreflectance for thin film measurements are given in detail, including equations and derivations for accurate data analysis.

This first volume of Thermoelectric Micro/Nano Generators comprehensively covers the fundamentals and state-of-the-art advances in thermoelectric property enhancement, computational methodolgy, various promising material systems, and metrology, which should be useful to a wide range of readers, from people who have some curiosity regarding this topic and beginners in the field, up to experts desiring guidelines and new clues for advanced development.

July 2023

Part 1Introduction to Materials Development

2Computational and Data-Driven Development of Thermoelectric Materials

Prashun GORAI1 and Michael TORIYAMA2

1Colorado School of Mines, Golden, CO, USA

2Northwestern University, Evanston, IL, USA

The development of thermoelectric (TE) materials has witnessed decades of progress. Experiments, analytical modeling and computations have been combined with solid-state physics and chemistry to discover, design and optimize TE materials. In the 21st century, computational and data-driven approaches have played a pivotal role in the development of new TE materials and the optimization of existing ones. Additionally, computations have enabled a deeper fundamental understanding of charge carrier and thermal transport, which in turn has led to design rules for TE materials.

Edisonian approaches are currently the most common for new TE material discovery, but are likely to make only a small dent in exploring vast chemical spaces. Computations have complemented experimental efforts through modeling of transport properties, for example, with semi-classical Boltzmann transport theory and high-throughput searches for new TE materials. These efforts have led to the creation of large, open-access computational databases of calculated transport and TE properties. In the last decade, computations have also significantly refined our understanding on the role of defects in TE materials and provided guidance for charge carrier tuning through doping. With the advent of data-driven approaches, TE material development will increasingly employ machine learning and material informatics.

In this chapter, we map the historical contributions of computations in TE material discovery and development, and highlight some recent advances. First, we discuss the general theory of charge carrier and phonon transport, and defect formation and doping. In the following section, we review the application of the theory in computational searches and development of TE materials. Several examples are briefly discussed in this section. The goal is to point the reader to relevant studies without delving into the details. Finally, we highlight several examples of high-throughput searches for new TE materials that use first-principles calculations and/or machine learning models. This chapter provides a broad overview of the computational and data-driven development of TE materials, and we hope that the readers will appreciate and recognize the important role of computations in future TE material development.

2.1. General theory

We review the general theoretical concepts underpinning the physics of TE materials. While concepts such as the TE figure of merit (zT), TE quality factor (β) and Boltzmann transport theory have been summarized elsewhere (Askerov 1994; Lundstrom 2002; Goldsmid 2013, 2017; Koumoto and Mori 2013), we review them here so that this chapter is self-contained. We begin by reviewing Boltzmann transport theory, which is the most commonly used framework for modeling and quantifying transport coefficients that are relevant to TE materials. We discuss the relaxation time approximation and provide brief derivations of the transport coefficients. Optimization of the TE performance critically depends on tuning the electronic carrier concentrations, which is achieved through native or extrinsic doping. In this context, we discuss the standard dilute defect model for calculating defect formation thermodynamics. Alloying is widely used by the TE community to enhance electronic transport, for example, through band convergence, and suppress phonon transport, for example, by increasing phonon–phonon scattering. We discuss computational methods to model alloys for predicting formation thermodynamics and calculating effective band structures.

2.1.1. Boltzmann transport theory

The theory of electronic (and phononic) transport in solids was initially inspired by the kinetic theory of gases, where electrons are treated as classical gaseous molecules. Three fundamental assumptions are imposed in these models: (1) collisions are assumed to instantaneously change the velocity of a particle, (2) interactions with nearby ions and other electrons are neglected during scattering events and (3) scattering events occur with a characteristic probability per unit time, 1/τ, where τ