scholarly journals Using iron sulphate to form both n-type and p-type pseudo-thermoelectrics: non-hazardous and ‘second life’ thermogalvanic cells

2020 ◽  
Vol 22 (18) ◽  
pp. 6062-6074
Author(s):  
Mark A. Buckingham ◽  
Kristine Laws ◽  
Jason T. Sengel ◽  
Leigh Aldous
Keyword(s):  
Second Life ◽  
Waste Heat ◽  
In Series ◽  
Iron Sulphate ◽  
P Type

Conventional electrically in-series thermogalvanic cells are proven options to chemically convert waste heat into electricity, but often utilise incompatible chemicals. This work reports significantly safer and more robust cell chemistry.

scholarly journals Thermoelectric Properties of Carbon Nanotubes

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4561 ◽  
Author(s):  
Nguyen T. Hung ◽  
Ahmad R. T. Nugraha ◽  
Riichiro Saito
Keyword(s):  
Carbon Nanotubes ◽  
Figure Of Merit ◽  
Waste Heat ◽  
Quantum Confinement Effect ◽  
Electrical Energy ◽  
High Seebeck Coefficient ◽  
Te Material ◽  
P Type ◽  
State Device ◽  
Solid State Device

Thermoelectric (TE) material is a class of materials that can convert heat to electrical energy directly in a solid-state-device without any moving parts and that is environmentally friendly. The study and development of TE materials have grown quickly in the past decade. However, their development goes slowly by the lack of cheap TE materials with high Seebeck coefficient and good electrical conductivity. Carbon nanotubes (CNTs) are particularly attractive as TE materials because of at least three reasons: (1) CNTs possess various band gaps depending on their structure, (2) CNTs represent unique one-dimensional carbon materials which naturally satisfies the conditions of quantum confinement effect to enhance the TE efficiency and (3) CNTs provide us with a platform for developing lightweight and flexible TE devices due to their mechanical properties. The TE power factor is reported to reach 700–1000 W / m K 2 for both p-type and n-type CNTs when purified to contain only doped semiconducting CNT species. Therefore, CNTs are promising for a variety of TE applications in which the heat source is unlimited, such as waste heat or solar heat although their figure of merit Z T is still modest (0.05 at 300 K). In this paper, we review in detail from the basic concept of TE field to the fundamental TE properties of CNTs, as well as their applications. Furthermore, the strategies are discussed to improve the TE properties of CNTs. Finally, we give our perspectives on the tremendous potential of CNTs-based TE materials and composites.

Sticky thermoelectric materials for flexible thermoelectric modules to capture low-temperature waste heat

MRS Advances ◽  
2020 ◽  
Vol 5 (10) ◽  
pp. 481-487 ◽  
Author(s):  
Norifusa Satoh ◽  
Masaji Otsuka ◽  
Yasuaki Sakurai ◽  
Takeshi Asami ◽  
Yoshitsugu Goto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Waste Heat ◽  
Air Cooling ◽  
Conductive Adhesives ◽  
Hot Plate ◽  
Low Thermal Conductivity ◽  
Te Modules ◽  
P Type ◽  
Flexible Thermoelectric

ABSTRACTWe examined a working hypothesis of sticky thermoelectric (TE) materials, which is inversely designed to mass-produce flexible TE sheets with lamination or roll-to-roll processes without electric conductive adhesives. Herein, we prepared p-type and n-type sticky TE materials via mixing antimony and bismuth powders with low-volatilizable organic solvents to achieve a low thermal conductivity. Since the sticky TE materials are additionally injected into punched polymer sheets to contact with the upper and bottom electrodes in the fabrication process, the sticky TE modules of ca. 2.4 mm in thickness maintained temperature differences of ca. 10°C and 40°C on a hot plate of 40 °C and 120°C under a natural-air cooling condition with a fin. In the single-cell resistance analysis, we found that 75∼150-µm bismuth powder shows lower resistance than the smaller-sized one due to the fewer number of particle-particle interfaces in the electric pass between the upper and bottom electrodes. After adjusting the printed wiring pattern for the upper and bottom electrodes, we achieved 42 mV on a hot plate (120°C) with the 6 x 6 module having 212 Ω in the total resistance. In addition to the possibility of mass production at a reasonable cost, the sticky TE materials provide a low thermal conductivity for flexible TE modules to capture low-temperature waste heat under natural-air cooling conditions with fins for the purpose of energy harvesting.

Power generation performance of π-structure thermoelectric device using NaCo2O4 and Mg2Si elements

2013 ◽  
Vol 1490 ◽  
pp. 185-190 ◽  
Author(s):  
Tomoyuki Nakamura ◽  
Kazuya Hatakeyama ◽  
Masahiro Minowa ◽  
Youhiko Mito ◽  
Koya Arai ◽  
...  
Keyword(s):  
Power Generation ◽  
Thermoelectric Power ◽  
Thermoelectric Properties ◽  
Waste Heat ◽  
Maximum Output Power ◽  
Magnesium Silicide ◽  
Thermoelectric Device ◽  
Maximum Output ◽  
Thermoelectric Power Generation ◽  
P Type

ABSTRACTThermoelectric power generation has been attracting attention as a technology for waste heat utilization in which thermal energy is directly converted into electric energy. It is well known that layered cobalt oxide compounds such as NaCo2O4 and Ca3Co4O9 have high thermoelectric properties in p-type oxide semiconductors. However, in most cases, the thermoelectric properties in n-type oxide materials are not as high. Therefore, n-type magnesium silicide (Mg2Si) has been studied as an alternative due to its non-toxicity, environmental friendliness, lightweight property, and comparative abundance compared with other TE systems. In this study, we fabricated π-structure thermoelectric power generation devices using p-type NaCo2O4 elements and n-type Mg2Si elements. The p- and n-type sintering bodies were fabricated by spark plasma sintering (SPS). To reduce the resistance at the interface between elements and electrodes, we processed the surface of the elements before fabricating the devices. The end face of a Mg2Si element was covered with Ni by SPS and that of a NaCo2O4 element was coated with Ag by silver paste and soldering.The thermoelectric device consisted of 18 pairs of p-type and n-type legs connected with Ag electrodes. The cross-sectional and thickness dimensions of the p-type elements were 3.0 mm × 5.0 mm × 7.6 mm (t) and those of the n-type elements were 3.0 mm × 3.0 mm × 7.6 mm (t). The open circuit voltage was 1.9 V and the maximum output power was 1.4 W at a heat source temperature of 873 K and a cooling water temperature of 283 K in air.

Structure Design for High Performance n-Type Polymer Thermoelectric Materials

2021 ◽  
Author(s):  
Qi Zhang ◽  
Hengda Sun ◽  
Meifang Zhu
Keyword(s):  
Conjugated Polymers ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Waste Heat ◽  
Building Blocks ◽  
Structure Design ◽  
Potential Candidate ◽  
Polymer Backbone ◽  
P Type ◽  
Polymer Thermoelectric

Abstract Organic thermoelectric (OTE) materials have been regarded as a potential candidate to harvest waste heat from complex, low temperature surfaces of objects and convert it into electricity. Recently, n-type conjugated polymers as organic thermoelectric materials have aroused intensive research in order to improve their performance to match up with their p-type counterpart. In this review, we discuss aspects that affect the performance of n-type OTEs, and further focus on the effect of planarity of backbone on doping efficiency and eventually the TE performance. We then summarize strategies such as implementing rigid n-type polymer backbone or modifying conventional polymer building blocks for more planar conformation. In the outlook part, we conclude forementioned devotions and point out new possibility that may promote the future development of this field.

Effect of Plating Layers on the Bonding Strength of p-Type Bi–Te Thermoelectric Elements

2021 ◽  
Vol 21 (8) ◽  
pp. 4503-4507
Author(s):  
Seong Min Yun ◽  
Injoon Son ◽  
Sung Hwa Bae
Keyword(s):  
Bonding Strength ◽  
Thermoelectric Module ◽  
Interface Layer ◽  
Ceramic Substrates ◽  
In Series ◽  
Cu Substrates ◽  
Solder Reaction ◽  
P Type ◽  
Substrate Defects ◽  
Solder Layer

In thermoelectric modules, multiple n-type and p-type thermoelectric elements are electrically connected in series on a Cu electrode that is bonded to a ceramic substrate. Defects in the bond between the thermoelectric elements and the Cu electrode could impact the performance of the entire thermoelectric module. This study investigated the effect of plating layers on the bonding strength of p-type Bi–Te thermoelectric elements. Ni and Pd electroplating was applied to Bi–Te thermoelectric elements; further, electroless Ni–P immersion gold (ENIG) plating was applied to Cu electrodes bonded to ceramic substrates. Forming a Pd/Ni electroplating layer on the surface of thermoelectric elements and an ENIG plating layer on the surface of the Cu electrode improved the bonding strength by approximately 3.5 times. When the Pd/Ni and ENIG plating layers were formed on Bi–Te elements and Cu substrates, respectively, the solderability greatly increased; as the solderability increased, the thickness of the diffusion layer formed with the solder layer increased. The improved bonding strength of the Pd/Ni plated thermoelectric element bonded on the ENIG plated substrate is attributed to the enhanced solderability due to the rapid inter-diffusion of Pd and Au into the solder layer and the formation of a stable and non-defected solder reaction interface layer.

Spray-on thermoelectric energy harvester

MRS Advances ◽  
2018 ◽  
Vol 4 (15) ◽  
pp. 851-855 ◽  
Author(s):  
Robert E. Peale ◽  
Seth Calhoun ◽  
Nagendra Dhakal ◽  
Isaiah O. Oladeji ◽  
Francisco J. González
Keyword(s):  
Thin Films ◽  
Power Generation ◽  
Energy Harvester ◽  
Waste Heat ◽  
Spray Deposition ◽  
Electrical Energy ◽  
Seebeck Coefficients ◽  
Thermoelectric Energy ◽  
P Type ◽  
Energy From Waste

AbstractThermoelectric (TE) thin films have promise for harvesting electrical energy from waste heat. We demonstrate TE materials and thermocouples deposited by aqueous spray deposition on glass. The n-type material was CdO doped with Mn and Sn. Two p-type materials were investigated, namely PbS with co-growth of CdS and doped with Na and Na2CoO4. Seebeck coefficients, resistivity, and power generation for thermocouples were characterized.

Topology Optimization of Multimaterial Thermoelectric Structures

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Xiaoqiang Xu ◽  
Yongjia Wu ◽  
Lei Zuo ◽  
Shikui Chen
Keyword(s):  
Topology Optimization ◽  
Thermoelectric Materials ◽  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Oil Refining ◽  
Numerical Verification ◽  
Temperature Range ◽  
Multiple Materials ◽  
P Type

Abstract A large amount of energy from power plants, vehicles, oil refining, and steel or glass making process is released to the atmosphere as waste heat. The thermoelectric generator (TEG) provides a way to reutilize this portion of energy by converting temperature differences into electricity using Seebeck phenomenon. Because the figures of merit zT of the thermoelectric materials are temperature-dependent, it is not feasible to achieve high efficiency of the thermoelectric conversion using only one single thermoelectric material in a wide temperature range. To address this challenge, the authors propose a method based on topology optimization to optimize the layouts of functional graded TEGs consisting of multiple materials. The multimaterial TEG is optimized using the solid isotropic material with penalization (SIMP) method. Instead of dummy materials, both the P-type and N-type electric conductors are optimally distributed with two different practical thermoelectric materials. Specifically, Bi2Te3 and Zn4Sb3 are selected for the P-type element while Bi2Te3 and CoSb3 are employed for the N-type element. Two optimization scenarios with relatively regular domains are first considered with one optimizing on both the P-type and N-type elements simultaneously, and the other one only on single P-type element. The maximum conversion efficiency could reach 9.61% and 12.34% respectively in the temperature range from 25 °C to 400 °C. CAD models are reconstructed based on the optimization results for numerical verification. A good agreement between the performance of the CAD model and optimization result is achieved, which demonstrates the effectiveness of the proposed method.

Experimental Analysis and a New Theoretical Model for Anomalously High Ideality Factors (n ≫ 2.0) in GaN-based p-n Junction Diodes

2003 ◽  
Vol 798 ◽  
Author(s):  
Jay M. Shah ◽  
Yunli Li ◽  
Thomas Gessmann ◽  
E. Fred Schubert
Keyword(s):  
Ideality Factor ◽  
Device Simulation ◽  
Superlattice Structure ◽  
In Series ◽  
Bulk Gan ◽  
Expected Values ◽  
Junction Diode ◽  
The One ◽  
P Type ◽  
Junction Structure

ABSTRACTDiode ideality factors of 2.0–8.0 have been reported in GaN-based p-n junctions. These values are much higher than the expected values of 1.0–2.0 as per the Sah-Noyce-Shockley theory. We propose a fundamentally new model for the high ideality factors obtained in GaN-based diodes. This model is based on the effect of moderately doped unipolar heterojunctions as well as metal–semiconductor junctions in series with the p-n junction. A relation for the effective ideality factor of a system of junctions is developed. A detailed experimental study is performed on diodes fabricated from two different structures, a bulk GaN p-n junction structure and a p-n junction structure incorporating a p-type AlGaN/GaN superlattice. Bulk GaN p-n junction diode displays an ideality factor of 6.9, whereas the one with the superlattice structure displays an ideality factor of 4.0. In addition, device simulation results further strengthen the model by showing that moderately doped unipolar heterojunctions are rectifying and increase the effective ideality factor of a p-n junction structure.

A new thermoelectric concept using large area PN junctions

2013 ◽  
Vol 1543 ◽  
pp. 3-8 ◽  
Author(s):  
R. Chavez ◽  
A. Becker ◽  
V. Kessler ◽  
M. Engenhorst ◽  
N. Petermann ◽  
...  
Keyword(s):  
Silicon Nanoparticles ◽  
Electrical Contacts ◽  
Large Area ◽  
Charge Generation ◽  
Thermally Induced ◽  
Pn Junction ◽  
In Series ◽  
Working Principle ◽  
Pn Junctions ◽  
P Type

ABSTRACTA new thermoelectric concept using large area silicon PN junctions is experimentally demonstrated. In contrast to conventional thermoelectric generators where the n-type and p-type semiconductors are connected electrically in series and thermally in parallel, we demonstrate a large area PN junction made from densified silicon nanoparticles that combines thermally induced charge generation and separation in a space charge region with the conventional Seebeck effect by applying a temperature gradient parallel to the PN junction. In the proposed concept, the electrical contacts are made at the cold side eliminating the need for contacts at the hot side allowing temperature gradients greater than 100K to be applied. The investigated PN junction devices are produced by stacking n-type and p-type nanopowder prior to a densification process. The nanoparticulate nature of the densified PN junction lowers thermal conductivity and increases the intraband traps density which we propose is beneficial for transport across the PN junction thus enhancing the thermoelectric properties. A fundamental working principle of the proposed concept is suggested, along with characterization of power output and output voltages per temperature difference that are close to those one would expect from a conventional thermoelectric generator.

Dispenser Printed Microscale Thermoelectric Generators for Powering Wireless Sensor Networks

2009 ◽  
Author(s):  
Alic Chen ◽  
Michael Koplow ◽  
Deepa Madan ◽  
Paul K. Wright ◽  
James W. Evans
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Waste Heat ◽  
Form Factors ◽  
Ambient Vibration ◽  
Wireless Sensor ◽  
Low Grade ◽  
Heat Sources ◽  
Active Monitoring ◽  
In Series

Wireless sensor networks (WSN) are a promising technology for ubiquitous, active monitoring in residential, industrial and medical applications. These nodes combine a radio transceiver, microcontroller and sensors into a low power package. A current bottleneck for widespread adoption of WSN’s is the power supplies. While the power demands can be somewhat alleviated through novel electronics, any primary battery will have a finite lifetime. Energy harvesting, from ambient vibration, light, and heat sources, offers an opportunity to significantly extend the lifetime of the nodes and possibly provide perpetual power. Thermal energy is an ideal source for WSNs due to the availability of low-grade ambient waste heat sources. Thermoelectric devices convert temperature gradients into DC electric power in compact form factors. Efficient device designs require hundreds of high-aspect ratio semi-conductor microelements fabricated electrically in series and thermally in parallel. This design requirement presents problems for standard microfabrication techniques due to thickness limitations of standard semiconductor processes. We present a new method of contact dispenser printing, specifically developed to additively create microscale generators. Initial materials performance results show promising results and are further detailed in this work.

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