French physicist Jean Charles Athanase Peltier discovered a key concept necessary for thermoelectric (TE) temperature control in 1834. His findings were so significant, TE devices are now commonly referred to Peltier devices. Since his work, there have been steady advancements in materials and design. Despite the technological sophistication Peltier devices, they are still less energy efficient than traditional compressor/evaporation cooling.
In the 1960's, Peltier devices were primarily made from Bismuth-Telluride (Bi2Te3) or Antimony-Telluride (Sb2Te3) alloys and had a peak efficiency (zT) of 1.1, meaning the electricity going in was only slightly less than the heat coming out. Since the 1960's there have been incremental advancements in alloy technology used in Peltier devices.
This schematic illustration shows the generation of dislocation arrays during the liquid-phase compaction process. The Te liquid (red) between the Bi0.5Sb1.5Te3 grains flows out during the compacting process and facilitates the formation of dislocation arrays embedded in low-energy grain boundaries.
Credit: Institute for Basic Science
In 2014, researchers in South Korea at IBS Center for Integrated Nanostructure Physics along with Samsung Advanced Institute of Technology, the Department of Nano Applied Engineering at Kangwon National University, the Department of Energy Science at Sungkyunkwan University, and Materials Science department at California Institute of Technology California, USA have formulated a new method for creating a novel and much more efficient TE alloy.
TE alloys are special because the metals have an incredibly high melting point. Instead of melting the metals to fuse them, they are combined through a process called sintering which uses heat and/or pressure to join the small, metallic granules.
The joint team, including IBS researchers, used a process called liquid-flow assisted sintering which combined all three antimony, bismuth and telluride granules into one alloy (Bi0.5Sb1.5Te3). Additional melted tellurium was used as the liquid between the Bi0.5Sb1.5Te3 granules to help fuse them into a solid alloy, and excess Te is expelled in the process.
By creating the alloy this way, the joints between the fused grains, also known as the grain boundaries, took on a special property. Traditionally sintered Bi0.5Sb1.5Te3 have thick, coarse joints which have led to a decrease in both thermal and electrical conductivity. The new liquid-phase sintering creates grain boundaries which are organized and aligned in seams called dislocation arrays. These dislocation arrays greatly reduce their thermal conduction, leading to an enhancement of their thermoelectric conversion efficiency.
In tests, the efficiency (zT) reached 2.01 at 320 K within the range of 1.86 ±0.15 at 320 K (46.85° C) for 30 samples, nearly doubling the industry standard. When the melt spun Bi0.5Sb1.5Te3 alloy is used in a Peltier cooler, the results are also significant. The new material was able achieve a temperature change of 81 K at 300 K (26.85° C).
The applications for such a material are abundant. As new fabrication techniques are developed, Peltier cooling devices may be used in place of traditional compression refrigeration systems. More importantly, as electrical vehicles and personal electronic devices become more ubiquitous in our daily lives, it is becoming increasingly necessary to have more efficient systems for localized electrical power generation and effective cooling mechanisms. This new thermoelectric alloy paves the way for the future of modern TE devices.
Sunny Kim | EurekAlert!
New concept for structural colors
18.05.2018 | Technische Universität Hamburg-Harburg
Saarbrücken mathematicians study the cooling of heavy plate from Dillingen
17.05.2018 | Universität des Saarlandes
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology