Scientists Create Crystals That Generate Electricity From Heat

Abstract Red Crystals

Previous thermoelectric devices use expensive and toxic elements. Now scientists have created inexpensive crystals composed of copper, manganese, germanium, and sulfur that can efficiently convert heat to electricity.

A synthetic sulfide mineral with thermoelectric properties.

In the effort to efficiently convert heat into electricity, easily accessible materials from harmless raw materials open up new perspectives in the development of safe and inexpensive so-called thermoelectric materials. A synthetic copper mineral acquires a complex structure and microstructure through simple changes in its composition, thereby laying the foundation for the desired properties, according to a study published recently in the journal Angewandte Chemie.

The novel synthetic material is composed of copper, manganese, germanium, and sulfur, and it is produced in a rather simple process, explains materials scientist Emmanuel Guilmeau, CNRS researcher at CRISMAT laboratory, Caen, France, who is the corresponding author of the study. “The powders are simply mechanically alloyed by ball-milling to form a precrystallized phase, which is then densified by 600 degrees Celsius. This process can be easily scaled up,” he says.

Thermoelectric materials convert heat to electricity. This is especially useful in industrial processes where waste heat is reused as valuable electric power. The converse approach is the cooling of electronic parts, for example, in smartphones or cars. Materials used in these kinds of applications have to be not only efficient, but also inexpensive and, above all, safe for health.

However, thermoelectric devices used to date make use of expensive and toxic elements such as lead and tellurium, which offer the best conversion efficiency. To find safer alternatives, Emmanuel Guilmeau and his team have turned to derivatives of natural copper-based sulfide minerals. These mineral derivatives are mainly composed of nontoxic and abundant elements, and some of them have thermoelectric properties.

Now, the team has succeeded in producing a series of thermoelectric materials showing two crystal structures within the same material. “We were very surprised at the result. Usually, slightly changing the composition has little effect on the structure in this class of materials,” says Emmanuel Guilmeau describing their discovery.

The team found that replacing a small fraction of the manganese with copper produced complex microstructures with interconnected nanodomains, defects, and coherent interfaces, which affected the material’s transport properties for electrons and heat.

Emmanuel Guilmeau says that the novel material produced is stable up to 400 degrees Celsius (750 degrees Fahrenheit). This is a temperature range that is well within the waste heat temperature range of most industries. He is convinced that, based on this discovery, novel cheaper, and nontoxic thermoelectric materials could be designed to replace more problematic materials.

Reference: “Engineering Transport Properties in Interconnected Enargite-Stannite Type Cu2+xMn1−xGeS4 Nanocomposites” by Dr. V. Pavan Kumar, S. Passuti, Dr. B. Zhang, Dr. S. Fujii, K. Yoshizawa, Dr. P. Boullay, Dr. S. Le Tonquesse, Dr. C. Prestipino, Prof. B. Raveau, Prof. P. Lemoine, Dr. A. Paecklar, Dr. N. Barrier, Prof. X. Zhou, Prof. M. Yoshiya, Dr. K. Suekuni, Dr. E. Guilmeau, 13 September 2022, Angewandte Chemie International Edition.
DOI: 10.1002/anie.202210600

Funding: Agence Nationale de la Recherche, Horizon 2020 Framework Programme, Japan Society for the Promotion of Science

7 Comments on "Scientists Create Crystals That Generate Electricity From Heat"

  1. Keep working on it. You will eventually discover those dilithium crystals they used in Star Treks “ships”. Youre on the right track. Dont stop there, keep going.

  2. This is exciting news! I can see this making hybrid vehicles way more efficient or hybridization of systems more practical rather than pure electric of purely combustion.

  3. Tourmaline:?? that aside, what amount of energy does it take to produce such cystal? input output ratio??

  4. Sooo creates energy from energy? Heat is energy? 😆

    • Oops misread the title, disregard… this is actually cool. Heat that’s not created by electric energy but by kinetic or other can be turned into electricity. Pretty neat.. wonder the applications.. I mean tesla and many others have the recharging brakes that use the Heat from the pads as slight charge.. can’t wait to hear more

  5. Economical seebeck modules are in sight. Wish to see them soon.
    Great work.

  6. Is this material available anywhere for engineers to look at and experiment with? I would be very interested in pursuing research on this.

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