A team of Michigan State University researchers have developed a new thermoelectric material based on natural minerals known as tetrahedrites, the most widespread sulfosalts on Earth.

Tetrahedrite Specimen. Click image for more info.

So where are these tetrahedrites?  They’re found pretty much anywhere there is dirt, common ordinary dirt.

The researchers, led by Donald Morelli, a professor of chemical engineering and materials science and directs MSU’s Center for Revolutionary Materials for Solid State Energy Conversion, developed the material.

Professor Donald Morelli in His Lab. Click image for more info.

Morelli said, “What we’ve managed to do is synthesize some compounds that have the same composition as natural minerals,” said Morelli, who also directs MSU’s Center for Revolutionary Materials for Solid State Energy Conversion. “The mineral family that they mimic is one of the most abundant minerals of this type on Earth – tetrahedrites. By modifying its composition in a very small way, we produced highly efficient thermoelectric materials.”

The wasted lost heat of combustion is stunning.  Thermoelectric materials could take that heat and turn it into something useful, like electricity.  The material and construction experimentation in the thermoelectric field is busy looking for the optimal answers.

Morelli said that while some new, more efficient materials have been discovered as of late, many of those are not suitable for large-scale applications because they are derived from rare or sometimes toxic elements, or the synthesis procedures are complex and costly.

“Typically you’d mine minerals, purify them into individual elements, and then recombine those elements into new compounds that you anticipate will have good thermoelectric properties,” he said. “But that process costs a lot of money and takes a lot of time. Our method bypasses much of that.”
The MSU researchers’ method involves the use of very common materials, grinding them to a powder, then using pressure and heat to compress into useable sizes.  “It saves tremendously in terms of processing costs,” he said.
The researchers expect this discovery could pave the way to many new, low-cost thermoelectric generation opportunities with applications that include waste heat recovery from industrial power plants, conversion of vehicle exhaust gas heat into electricity, and generation of electricity in home-heating furnaces.

The research paper ‘High Performance Thermoelectricity in Earth-Abundant Compounds Based on Natural Mineral Tetrahedriteshas’ been published in the online journal Advanced Energy Materials.

The lab and prototype builds are yet to come, so we’ll wait for the efficiency numbers and the costs.  For fundamental research and experimentation, this looks like a great result.


2 Comments so far

  1. Matt Musson on November 29, 2012 7:04 AM

    If they are so abundant in the earth’s crust – they must be naturally generating thermoelectric energy. Wouldn’t that have significant impacts on the biosphere and global climate?

  2. Steve on November 29, 2012 5:35 PM

    Thermoelectric power generation requires a relatively large temperature gradient to generate any kind of net voltage. The tetrahedrites in the ground may do this locally to some extent, but it’s nothing significant.

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