researchers at the university of utah recently discovered that a combination of calcium, cobalt, and terbium creates an efficient, inexpensive, and non-toxic material that generates thermoelectric energy through temperature gradients, according to a report on the school website.
university of utah materials science and engineering professor ashutosh tiwari and his team have an inexpensive and bio-friendly material that can generate electricity through a thermoelectric process. (dan hixson/university of utah college of engineering)
the engineers were looking for thermoelectric materials that would be eco-friendly and non-toxic for humans. when ca3co4og is placed between a layer that is hot and one that is cold, energy moves from one end to the other. as the energy moves across the gradient, it produces an electric charge.
in experiments, the utah researchers discovered that only one degree of temperature difference was necessary to produce a charge.
according to the utah website, “it could be built into jewelry that uses body heat to power implantable medical devices such as blood-glucose monitors or heart monitors. it could be used to charge mobile devices through cooking pans or in cars where it draws from the heat of the engine. airplanes could generate extra power by using heat from within the cabin versus the cold air outside. power plants also could use the material to produce more electricity from the escaped heat the plant generates.”
a feature on the discovery in smithsonian magazine added, “because the material is such a new discovery, saini says that they are in the middle of analyzing the exact grams to watts measurement; however, their rough estimate shows that for one watt of power to be generated, they need about five grams of the material.”
the article noted that waste heat is an important consideration from energy producers and this discovery could have long-term ramifications, particularly because it avoids materials such as cadmium, telluride, or mercury, which are all harmful to humans (and not as stable as ca3co4og).
“also, prior thermoelectric materials were not scalable because they were derived from manufacturing or fabricating single crystals, which is both expensive and challenging,” the article continued. “[this] chemical combination may allow for large-scale application of this thermoelectric technology because the chemicals are readily available to mix up and cook to derive the non-toxic material, making it easier to manufacture in larger batches. this makes the discovery a possible game changer.”
the research was recently published in scientific reports. the abstract stated:
“the potential of thermoelectric materials to generate electricity from the waste heat can play a key role in achieving a global sustainable energy future. in order to proceed in this direction, it is essential to have thermoelectric materials that are environmentally friendly and exhibit high figure of merit, zt. oxide thermoelectric materials are considered ideal for such applications.
“high thermoelectric performance has been reported in single crystals of ca3co4o9. however, for large scale applications single crystals are not suitable and it is essential to develop high-performance polycrystalline thermoelectric materials. in polycrystalline form, ca3co4o9 is known to exhibit much weaker thermoelectric response than in single crystal form.
“here, we report the observation of enhanced thermoelectric response in polycrystalline ca3co4o9 on doping tb ions in the material. polycrystalline ca3−xtbxco4o9 (x = 0.0–0.7) samples were prepared by a solid-state reaction technique. samples were thoroughly characterized using several state of the art techniques including xrd, tem, sem and xps.
“temperature dependent seebeck coefficient, electrical resistivity and thermal conductivity measurements were performed. a record zt of 0.74 at 800 k was observed for tb doped ca3co4o9 which is the highest value observed till date in any polycrystalline sample of this system.”
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