WO2005098981A1 - Applications thermoelectriques de composites de ceramiques et de nanotubes de carbone - Google Patents

Applications thermoelectriques de composites de ceramiques et de nanotubes de carbone Download PDF

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Publication number
WO2005098981A1
WO2005098981A1 PCT/US2004/007187 US2004007187W WO2005098981A1 WO 2005098981 A1 WO2005098981 A1 WO 2005098981A1 US 2004007187 W US2004007187 W US 2004007187W WO 2005098981 A1 WO2005098981 A1 WO 2005098981A1
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Prior art keywords
carbon nanotubes
composite
improvement
volume
thermoelectric
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PCT/US2004/007187
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English (en)
Inventor
Guodong Zhan
Joshua D. Kuntz
Amiya K. Mukherjee
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The Regents Of The University Of Califonria
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Priority to PCT/US2004/007187 priority Critical patent/WO2005098981A1/fr
Publication of WO2005098981A1 publication Critical patent/WO2005098981A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/10—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects
    • H10N10/17—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects characterised by the structure or configuration of the cell or thermocouple forming the device
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/85—Thermoelectric active materials
    • H10N10/851—Thermoelectric active materials comprising inorganic compositions
    • H10N10/855—Thermoelectric active materials comprising inorganic compositions comprising compounds containing boron, carbon, oxygen or nitrogen

Definitions

  • thermoelectric materials and devices resides in the field of thermoelectric materials and devices, and in particular, in methods and materials for improving the energy conversion efficiencies of devices that utilize thermoelectric effects.
  • the Seebeck effect is the spontaneous development of an open-circuit emf in a circuit formed by joining two dissimilar conductors when the junctions of the two conductors are maintained at different temperatures.
  • the emf arises because the higher energies of the electrons at the hot junction produce a net diffusion of electrons (or charge carriers) toward the cold junction, creating a charge imbalance that results in an electric potential between the hot and cold junctions.
  • the magnitude of the electric potential is roughly proportional to the temperature differential, and the proportionality factor is termed the Seebeck coefficient.
  • semiconductors are used as the conducting media, and the circuit is formed by pairing n-type and p-type semiconductors and imposing a temperature gradient across them in parallel while electrically connecting them in series.
  • the temperature gradient produces net charges of opposing polarities and hence a voltage between elect ⁇ cally joined ends of the semiconductors.
  • thermoelectric power does not require moving parts.
  • Devices and generators of thermoelectric power thus offer greater reliability and service life by the avoidance of mechanical wear, plus a lower operating cost due to less need for maintenance.
  • the lack of a need for operator attendance also permits thermoelectric devices to be used in hostile environments such as those at high temperatures.
  • a still further advantage is the ability of these devices to make productive use of waste heat from industrial operations or of heat that is readily available from natural sources.
  • the efficiency of the conversion of thermal energy to electrical energy is a function of several variables and has two components, the Carnot efficiency, which is the ratio of the temperature differential to the absolute temperature at the hot junction, and a dimensionless parameter known as the thermoelectric figure of merit, which is represented by ZT.
  • T is the absolute temperature at the hot junction
  • Z ⁇ 2 /( ⁇ p), where ⁇ is the Seebeck coefficient, K is the thermal conductivity, and p is the electrical resistivity.
  • thermoelectric materials of high efficiency first resulted in investigations of bismuth telluride and lead telluride. These were followed by the development of Si x Ge ⁇ - x alloys, particularly for high-temperature use in space vehicles. Optimizations of these alloys were made by doping the alloys as n-type and p-type semiconductors and varying the doping levels and alloy compositions, these optimizations were unsuccessful however in obtaining ZT values greater than approximately 1, which is not high enough to support commercially viable applications.
  • thermoelectric materials of greater efficiency arose with the development of nanotechnology and further by the discovery of carbon nanotubes in 1991.
  • Nanostructured materials in general are promising candidates for thermoelectric materials in view of the quantum confinement effect of the charge carriers of nanostructures and the size effect of the heat carriers.
  • the quantum confinement of the charge carriers has the potential of increasing the Seebeck coefficient and the electrical conductivity, while the enhanced boundary scattering due to the small size of the heat carriers has the potential of reducing the thermal conductivity.
  • increasing the electrical conductivity i.e., lowering the electrical resistivity
  • reducing the thermal conductivity both result in an increase in the thermoelectric figure of merit.
  • thermoelectric materials with a high degree of thermoelectric efficiency owing to a high electrical conductivity and a low thermal conductivity. These qualities render these composites highly effective as materials for use in thermoelectric power generation under the Seebeck effect, and in the transport of thermal energy, either by absorption or evolution, under the Peltier and Thomson effects. It has also been discovered that these composites exhibit a Seebeck coefficient whose rate of increase with increasing temperature is approximately linear. A still further discovery is that composites of this invention, without further doping, function as p-type conductors.
  • the present invention resides in methods of generating thermoelectric power, of transporting thermal energy by either heating or cooling, of both generating thermoelectric power and transporting thermal energy, and utilizing these materials as thermoelectric media and in thermoelectric devices in which these composites serve as thermoelectric conductors.
  • a ceramic composite in accordance with this invention is used in place of the conductors of the prior art.
  • a ceramic composite in accordance with this invention is used as the electrical and thermal energy transport medium.
  • a ceramic composite in accordance with this invention serves as at least one of the two conductors, and, when only one, preferably the p-type conductor.
  • Prefened composites of this invention are those formed from nano-sized ceramic particles and from single-wall carbon nanotubes. It is further preferred that the composites are formed by densification of mixtures of these materials, particularly by spark plasma sintering to achieve densities approaching 100% theoretical density. In addition to their unique thermoelectric properties, these highly dense materials exhibit high fracture toughness and mechanical properties in general.
  • metal oxide ceramics are alumina, yttria, magnesium oxide, zirconia, magnesia spinel, titania, calcium aluminate, cerium oxide, chromium oxide, and hafnium oxide. Further examples are combinations that include non-metal oxides such as silica. Still further examples are metallic oxides that also contain elements in addition to metals and oxygen, such as SiAlON and A1ON. Combinations of any of these metal oxides can also be used.
  • a metal oxide that is currently of particular interest is alumina, either ⁇ -alumina, ⁇ -alumina, or a mixture of both. When the metal oxide includes alumina and the composite is formed by consolidating a powder mixture that includes ⁇ -alumina powder, the ⁇ -alumina will often convert to ⁇ -alumina during the consolidation.
  • Carbon nanotubes are polymers of pure carbon. Both single-wall and multi-wall carbon nanotubes can be used in the practice of this invention, although single- wall carbon nanotubes are preferred. Single-wall and multi-wall carbon nanotubes are known in the art and the subject of a considerable body of published literature. Examples of literature describing carbon nanotubes are Dresselhaus, M.S., et al., Science ofFullerenes and Carbon Nanotubes, Academic Press, San Diego (1996), and Ajayan, P.M., et al., "Nanometre- Size Tubes of Carbon,” Rep. Prog. Phys. 60 (1997): 1025-1062.
  • a single-wall carbon nanotube is a single graphene sheet rolled into a seamless cylinder with either open or closed ends. When closed, the ends are capped either by half fullerenes or by more complex structures such as pentagonal lattices.
  • the average diameter of a single-wall carbon nanotube typically ranges of 0.5 to 100 nm, and most often, 0.5 to 10 nm, 0.5 to 5 nm, or 0.7 to 2 nm.
  • the aspect ratio, i.e., length to diameter typically ranges from about 25 to about 1,000,000, and most often from about 100 to about 1,000.
  • a nanotube of 1 nm diameter may thus have a length of from about 100 to about 1,000 nm.
  • Nanotubes frequently exist as "ropes," which are bundles of 3 to 500 single-wall nanotubes held together along their lengths by van der Waals forces. Individual nanotubes often branch off from a rope to join nanotubes of other ropes. Multi- walled carbon nanotubes are two or more concentric cylinders of graphene sheets of successively larger diameter, forming a layered composite tube bonded together by van der Waals forces, with a distance of approximately 0.34 nm between layers. Further descriptions of carbon nanotubes are given by Peigney, A., et al., “Carbon nanotubes in novel ceramic matrix nanocomposites,” Ceram. Inter. 26 (2000) 677-683.
  • Carbon nanotubes can be prepared by arc discharge between carbon electrodes in an inert gas atmosphere. This process results in a mixture of single-wall and multi-wall nanotubes, although the formation of single-wall nanotubes can be favored by the use of transition metal catalysts such as iron or cobalt.
  • Single-wall nanotubes can also be prepared by laser ablation, as disclosed by Thess, A., et al., "Crystalline Ropes of Metallic Carbon Nanotubes," Science 273 (1996): 483-487, and by Witanachi, S., et al., "Role of Temporal Delay in Dual-Laser Ablated Plumes," J. Vac. Sci. Technol. A 3 (1995): 1171-1174.
  • a further method of producing single-wall nanotubes is the HiPco process disclosed by Nikolaev, P., et al., "Gas-phase catalytic growth of single- walled carbon nanotubes from carbon monoxide," Chem. Phys. Lett. 313, 91-97 (1999), and by Bronikowski M. J., et al., "Gas-phase production of carbon single-walled nanotubes from carbon monoxide via the HiPco process: A parametric study," J. Vac. Sci. Technol. 19, 1800-1805 (2001).
  • Preferred starting materials for the composites of this invention are powder mixtures of the ceramic material and the carbon nanotubes.
  • the particle size of the ceramic material can vary while still achieving the benefits of the presence of the carbon nanotubes when consolidated and densified.
  • the ceramic particles can thus be micron-sized, sub-micron- sized, or nano-sized.
  • micron-sized refers to particles having diameters that are greater than 1 micron
  • sub-micron-sized refers to particles whose diameters are within the range of 100 nm to 1,000 nm, typically 150 nm or above
  • nano-sized refers to particles whose diameters are less than 100 nm, particularly 50 nm or below.
  • the particle size of the starting ceramic material decreases, the final density of the densified composite product increases. Accordingly, particles that are less than 500 nm in diameter on the average are preferred, and those that are less than 100 nm in diameter are particularly preferred.
  • the carbon nanotubes may be single-wall nanotubes, multi-wall carbon nanotubes, or mixtures of single-wall and multi-wall carbon nanotubes. It is preferred however that the mixtures, and the final product as well, be free of all carbon nanotubes except single- wall carbon nanotubes, or if double- wall or multi-wall carbon nanotubes are present, that the carbon nanotubes in the mixture be predominantly single-wall carbon nanotubes.
  • the relative amounts of ceramic material and carbon nanotubes can vary, although the mechanical properties and possibly the performance characteristics may vary with the proportions of the carbon nanotubes. In most cases, best results will be achieved with composites in which the carbon nanotubes constitute from about 1% to about 50%, preferably from about 2% to about 30%, and most preferably from about 3% to about 20%, by volume of the composite.
  • the volumes used in determining the volume percents referred to herein are calculated from the weight percents of the bulk starting materials and their theoretical densities.
  • the carbon nanotubes can be dispersed through the ceramic powder by conventional means to form a homogeneously dispersed powder mixture, although a preferred method of preparing such a mixture is by suspending the materials together in a common liquid suspending medium. Any readily removable, low-viscosity, inert suspending liquid, such as a low molecular weight alcohol (ethanol, for example), can be used.
  • ethanol low molecular weight alcohol
  • Carbon nanotubes are available from commercial suppliers in a paper-like form, and can be dispersed in ethanol and other liquid suspending agents with the assistance of ultrasound.
  • a preferred means of mixing to achieve a uniform dispersion is ball-milling using conventional rotary mills with the assistance of tumbling balls.
  • the sizes of the balls, the number of balls used per unit volume of powder, the rotation speed of the mill, the temperature at which the milling is performed, and the length of time that milling is continued can all vary widely. Best results will generally be achieved with a milling time ranging from about 4 hours to about 50 hours.
  • the degree of mixing may also be affected by the "charge ratio,” which is the ratio of the mass of the balls to the mass of the powder. A charge ratio of from about 20 to about 100 will generally provide proper mixing.
  • the qualities of the product can be enhanced by mechanical activation of the ceramic particles prior to consolidating them into a composite.
  • Mechanical activation is likewise achieved by methods known in the art and is typically performed in centrifugal, oscillating or planetary mills that apply centrifugal, oscillating and/or planetary action to the powder mixture with the assistance of grinding balls.
  • the grinding balls produce impacts of up to 20 g (20 times the acceleration due to gravity). Variables such as the sizes of the milling balls, the number of milling balls used per unit amount of powder, the temperature at which the milling is performed, the length of time that milling is continued, and the energy level of the mill such as the rotational speed or the frequency of impacts, can vary widely.
  • the number and size of the milling balls relative to the amount of powder is typically expressed as the "charge ratio,” which is defined as the ratio of the mass of the milling balls to the mass of the powder.
  • Preferred milling frequencies are at least about 3, and preferably about 3 to 30 cycles per second or, assuming two impacts per cycle, at least about 6, and preferably about 6 to about 60 impacts per second.
  • Consolidation of the powder mixture into a continuous mass is preferably performed by uniaxial compression.
  • the composite will further benefit if densified to a high density as it is being consolidated.
  • Optimal densities are those that approach full theoretical density, which is the density of the material as determined by volume-averaging the densities of each of its components.
  • the term "relative density” is used herein to denote the actual density expressed as a percent of the theoretical density.
  • Preferred composites thus have relative densities of 90% or above, more preferably at least 95%, still more preferably at least 98%, and most preferably at least 99%.
  • Uniaxial compression is preferably performed in combination with electric field- assisted sintering.
  • One method of performing this type of sintering is by passing a pulsewise DC electric cunent through the dry powder mixture or through a consolidated mass of the mixture while applying pressure.
  • a description of electric field-assisted sintering and of apparatus in which this process can be performed is presented by Wang, S.W., et al., referenced above. While the conditions may vary, best results will generally be obtained with a densification pressure exceeding 10 MPa, preferably from about 10 MPa to about 200 MPa, and most preferably from about 40 MPa to about 100 MPa.
  • the prefened current is a pulsed DC cunent of from about 250 A/cm 2 to about 10,000 A/cm 2 , most preferably from about 500 A/cm 2 to about 2,500 A/cm 2 .
  • the duration of the pulsed cunent will generally range from about 1 minute to about 30 minutes, and preferably from about 1.5 minutes to about 5 minutes.
  • Prefened temperatures are within the range of from about 800°C to about 1,500°C, and most preferably from about 900°C to about 1,400°C.
  • the compression and sintering are preferably performed under vacuum. Prefened vacuum levels for the densification are below 10 Ton, and most preferably below 1 Ton.
  • Thermoelectric devices and power generators in accordance with this invention can assume configurations cunently known in the art except for the substitution of the composites of the present invention for the conducting media.
  • the composites can thus be doped with conventional doping materials to form n-type or p-type semiconductors, and n-type and p-type semiconductors can be paired and connected electrically and thermally to serve the needs of the device, which is either to generate power from a temperature gradient or to heat or cool due to the imposition of an electric potential.
  • the n-type and p-type semiconductors will be thermally connected in parallel together with externally applied temperature gradient across both, and electrically connected in series to form an electric circuit.
  • the composites of the present invention can serve as one or both of the semiconductors, appropriately doped, or in the case where the composite serves as the p-type semiconductor, the composite can serve this function without doping in view of its spontaneous p-type behavior.
  • the alumina nanopowder was then combined the 3Y-TZP nanopowder and the mixture was mixed by ball-milling for 24 hours using zirconia milling media.
  • the ball-milled mixture was then added to the nanotube dispersion, and the combined dispersion was sieved with a 200-mesh sieve, then ball-milled for 24 hours (in ethanol) using zirconia milling media, then dried to form a dry powder mixture.
  • the proportions used were such that the final mixture consisted of 10% single-wall carbon nanotubes, 20% 3Y-TZP, and 70% alumina, all by volume.
  • the powder mixture was placed on a graphite die of inner diameter 19 mm and cold-pressed at 200 MPa.
  • the cold-pressed powder mixture was then sintered on a Dr. Sinter 1050 Spark Plasma Sintering System (Sumitomo Coal Mining Company, Japan) under vacuum. Electric field-assisted sintering was then performed at an applied pressure of 80 MPa with a pulsed DC cunent of about 5,000 A maximum and a maximum voltage of 10 V.
  • the pulses had a period of about 3 ms and followed a pattern of 12 cycles on and 2 cycles off.
  • the samples were heated to 600°C in 2 minutes and then heated further at rates of 550°C/min to 600°C/min to 1,150 °C where they were held for 3 minutes.
  • the temperature was monitored with an optical pyrometer focused on a depression in the graphite die measuring 2 mm in diameter and 5 mm in depth.
  • thermoelectric measuring apparatus RZ2001K, Ozawa Scientific Co., Japan
  • Electrical conductivity measurements were performed at 373-673 K by a DC four-probe technique in air.
  • thermopower measurement the temperature gradient in the specimen was generated by passing cool air in an alumina protection tube placed near one end of the specimen. The temperature difference between the two ends was controlled at 2-15 K by varying the flow rate of air. Measurements of thermopower as a function of temperature gradient indicated a linear dependence and the Seebeck coefficient were calculated from the slope of the thermopower-temperature line. The values thus determined were as follows:
  • the dependence of the Seebeck coefficient on temperature indicated by the data in this table is approximately linear.
  • the Seebeck coefficient at the lowest temperature (28.5 ⁇ V/K) is comparable to that of aligned ropes of single-wall carbon nanotubes (approximately 27 ⁇ K/V at 300 K), as reported by Hone, J., et al., Appl. Phys. Lett. 77(5): 666-8 (2000).
  • the fracture toughness of the material was 8.5 MPam" , and the room- temperature conductivity was 3,638 S/m.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Physics & Mathematics (AREA)
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  • Crystallography & Structural Chemistry (AREA)
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Abstract

L'invention concerne des composites formés par solidification de mélanges de poudres matériaux céramiques et de nanotubes de carbone. On a constaté que ces composites présentaient des propriétés favorables en tant que matériaux thermoélectriques utilisés dans des dispositifs permettant de produire de l'énergie électrique par effet Seebeck ou de produire un flux thermique par effet Peltier ou par effet Thomson.
PCT/US2004/007187 2004-03-08 2004-03-08 Applications thermoelectriques de composites de ceramiques et de nanotubes de carbone WO2005098981A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012054504A3 (fr) * 2010-10-18 2013-01-10 Wake Forest University Appareil thermoélectrique et ses applications
CN104198908A (zh) * 2014-09-12 2014-12-10 江南大学 半导体温差片特性实验仪
US10840426B2 (en) 2013-03-14 2020-11-17 Wake Forest University Thermoelectric apparatus and articles and applications thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6231744B1 (en) * 1997-04-24 2001-05-15 Massachusetts Institute Of Technology Process for fabricating an array of nanowires
US20030047204A1 (en) * 2001-05-18 2003-03-13 Jean-Pierre Fleurial Thermoelectric device with multiple, nanometer scale, elements

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6231744B1 (en) * 1997-04-24 2001-05-15 Massachusetts Institute Of Technology Process for fabricating an array of nanowires
US20030047204A1 (en) * 2001-05-18 2003-03-13 Jean-Pierre Fleurial Thermoelectric device with multiple, nanometer scale, elements

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
GRIGORIAN ET AL.: "Transport properties of single-walled carbon nanotubes", IEEE 17TH INTERNATIONAL CONFERENCE ON THERMOELECTRICS, 1998, pages 358 - 361, XP002983392 *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012054504A3 (fr) * 2010-10-18 2013-01-10 Wake Forest University Appareil thermoélectrique et ses applications
CN103283049A (zh) * 2010-10-18 2013-09-04 韦克森林大学 热电装置及其应用
AU2011317206B2 (en) * 2010-10-18 2015-06-18 Wake Forest University Thermoelectric apparatus and applications thereof
EP3041057A3 (fr) * 2010-10-18 2016-09-28 Wake Forest University Appareil thermoelectrique et ses applications
CN103283049B (zh) * 2010-10-18 2017-03-15 韦克森林大学 热电装置及其应用
CN106848049A (zh) * 2010-10-18 2017-06-13 韦克森林大学 热电装置及其应用
US10868077B2 (en) 2010-10-18 2020-12-15 Wake Forest University Thermoelectric apparatus and applications thereof
US10840426B2 (en) 2013-03-14 2020-11-17 Wake Forest University Thermoelectric apparatus and articles and applications thereof
CN104198908A (zh) * 2014-09-12 2014-12-10 江南大学 半导体温差片特性实验仪

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