Published on : Jun 25, 2019
Scientists at the Texas Center for Superconductivity, University of Huston, have reported a major discovery that sheds more light on the asymmetrical thermoelectric performance. This discovery was published in Science Advances journal.
Asymmetrical thermoelectric performance is a phenomenon, which occurs when a positive charge carrying material is highly efficient in a form that is radically less effective when it carries negative charge in the same form, or vice versa.
The scientists were already aware of the performance of the material in the two forms, viz. ‘p-type’ and ‘n-type’ for the positive and negative charges respectively. However, majority of materials do not exist in both forms. Also, at times, one form shows higher efficiency than the other.
New Complex Compound Provides Sense of Clarity to the Study
The scientists working on these thermoelectric materials are trying to find a clean energy source that will be able to produce significant power through heat waste. The researchers reported to have developed a new model for better understanding the existing disparity in the performance of the aforementioned formulation types. The researchers then used the model to determine new materials showing promise to create power from heat wastage.
The scientists have now been able to synthesize one such predicted material. The material is a zirconium-cobalt-bismuth compound. This compound showed a good 10.6% heat to electricity conversion efficiency at both cold and hot side for both the n-type and p-type forms. The material showed about 86 degrees Fahrenheit or 303 Kelvin and about 1310 degree Fahrenheit or 983 Kelvin for cold and hot sides respectively.
Researchers found that some materials show asymmetrical performance because of the way charge moves at different rates in its two forms. If the charge movement for both the p-type and n-type is similar then that leads to a similar thermoelectric performance for both types. Using this theory, researchers used the mobility ratio to determine the performances of previously untested materials.
The researchers are now working towards how to develop a corresponding material type once a highly efficient p-type or n-type material is found. With the insights gained from the study of unsymmetrical performance, researchers will be able to predict compounds with efficient performance in both charge types.