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UH RESEARCHERS DISCOVER NEW MATERIAL TO PRODUCE CLEAN ENERGY

March 04, 2015

UH RESEARCHERS DISCOVER NEW MATERIAL TO PRODUCE CLEAN ENERGY

New Material Shows Value of High Power Factor, High-Output Power Materials

Houston, March 4, 2015 – Researchers at the University of Houston have created a new thermoelectric material, intended to generate electric power from waste heat – from a vehicle tailpipe, for example, or an industrial smokestack – with greater efficiency and higher output power than currently available materials.

The material, germanium-doped magnesium stannide, is described in the current issue of the Proceedings of the National Academy of Sciences. Zhifeng Ren, lead author of the article and M.D. Anderson Chair professor of physics at UH, said the new material has a peak power factor of 55, with a figure of merit – a key factor to determine efficiency – of 1.4.

The new material – the chemical compound is Mg2Sn0.75Ge0.25 – is important in its own right, Ren said, and he has formed a company, called APower, to commercialize the material, along with frequent collaborator Gang Chen of the Massachusetts Institute of Technology and two former students.

But he said another key point made in the paper is the importance of looking for materials with a high power factor, or output power density, in addition to the traditional focus on a high figure of merit, or efficiency, commonly referred to as ZT.

“Everyone pursued higher ZT,” he said. “That’s still true. But the way everybody pursued higher ZT is by reducing thermal conductivity. We were, too. But the reduction of thermal conductivity is limited. We need to increase the power factor. If thermal conductivity remains the same and you increase the power factor, you get higher ZT.”

Thermoelectric materials produce electricity by exploiting the flow of current from a warmer area to a cooler area. In the germanium-doped magnesium stannide, the current is carried by electrons.

“Pursuing high ZT has been the focus of the entire thermoelectric community …” the researchers wrote. “However, for practical applications, efficiency is not the only concern, and high output power density is as important as efficiency when the capacity of the heat source is huge (such as solar heat), or the cost of the heat source is not a big factor (such as waste heat from automobiles, steel industry, etc.)”

Germanium-doped magnesium stannide has a fairly standard figure of merit, at 1.4, but a high power factor, at 55, the researchers report. That, coupled with a raw material cost of about $190 per kilogram, according to the U.S. Geological Survey Data Series, makes it commercially viable, they said.

Ren, who also is a principal investigator at the Texas Center for Superconductivity at UH, said several competing materials have lower power factors and also more expensive raw materials.

The material was created through mechanical ball milling and direct current-induced hot pressing. It can be used with waste-heat applications and concentrated solar energy conversion at temperatures up to 300 degrees Centigrade, or about 572 degrees Fahrenheit, Ren said. He said typical applications would include use in a car exhaust system to convert heat into electricity to power the car’s electric system, boosting mileage, or in a cement plant, capturing waste heat from a smokestack to power the plant’s systems.

In addition to Ren, researchers on the paper include Weishu Liu, Hee Seok Kim, Shuo Chen, Qing Jie, Bing Lv and Paul Ching-Wu Chu, all of the UH physics department and the Texas Center for Superconductivity; Mengliang Yao, Zhensong Ren and Cyril P. Opeil of Boston College, and Stephen Wilson of the University of California at Santa Barbara.

UH Physicist Shuo Chen Awarded Welch Professorship

October 14, 2014
UH Physicist Shuo Chen Awarded Welch Professorship

Shuo Chen, an assistant professor in the Department of Physics, has been awarded a Robert A. Welch Professorship in High Temperature Superconductivity and Materials Physics from the Texas Center for Superconductivity at the University of Houston (TcSUH). The Robert A. Welch Foundation created the two-year professorships to support outstanding faculty, research faculty and visiting scientists.

The appointment was effective Oct. 1.

“Understanding physical properties of materials are of great importance for their vast applications,” Chen said. “I am appreciative of the support from the Robert A. Welch Professorship to accelerate my work on exploring novel physics in materials for electronics, energy and superconductivity.”

Her research includes synthesis, in situ electron microscopy and device application of materials. She aims to discover new physics and materials in superconductivity, electrocatalysis for fuel and energy generation, thermoelectrics for heat-electricity conversion, batteries for energy storage and phase change materials for electronics.

She is particularly interested in interfacial mass and electrical and thermal transport properties in materials. Such transport phenomena can play dominant roles in materials, especially where there are a large amount of nanostructures.

With her expertise in materials synthesis and in situ electron microscopy, she intends to fabricate individual nanostructures and interfaces, then apply in situ atomic resolution electron microscopy for simultaneously acquiring structures and transport properties in nanoscale interfaces with controllable temperature, electrical and mechanical conditions. Ultimately, she plans to apply the fundamental understanding gained to design superior materials for applications.

Allan J. Jacobson, TcSUH director and the Robert A. Welch Chair of Science in the UH chemistry department, said he is pleased the Center for Superconductivity is expanding its energy materials program.

“We look forward to Chen’s exciting research,” he said.

For more information, read the original news release.

October issue of TMC Pulse & TMC News

October 09, 2014
October issue of TMC Pulse & TMC News

The October issue of TMC Pulse features profiles of some of the pioneering talent responsible for the many breakthroughs and discoveries made at Texas Medical Center.

For more information, read the original news release.

UH Researchers Begin Work on $1.8 Million Design-and-Build Project

September 04, 2014
UH Researchers Begin Work on $1.8 Million Design-and-Build Project | Money Will Fund Building New Equipment to Use in Defense Research, Cut Costs

HOUSTON, Sept. 4, 2014 - Paul Chu, T.L.L. Temple Chair of Science and founding director of the Texas Center for Superconductivity at the University of Houston, will lead a group of investigators as they build a one-of-a-kind piece of equipment designed to further their research and ultimately help make superconductivity and thermoelectricity more commercially viable. See enclosed release for more information.

For more information, read the original news release.

Superconductivity Researcher Awarded Welch Professorship | Chemist Jakoah Brgoch Works to Develop Energy-Efficient Materials

August 29, 2014
Superconductivity Researcher Awarded Welch Professorship | Chemist Jakoah Brgoch Works to Develop Energy-Efficient Materials

HOUSTON, Aug. 29, 2014 - Jakoah Brgoch, an assistant professor in the Department of Chemistry, has been awarded a Robert A. Welch Professorship in High Temperature Superconductivity and Chemical Materials from the Texas Center for Superconductivity at the University of Houston (TcSUH). The Robert A. Welch Foundation created the professorships to recruit and retain outstanding faculty, research faculty and visiting scientists. See enclosed release for more information.

For more information, read the original news release.

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