Thermoelectric power generation is one of the most promising techniques to use the huge amount of waste heat and solar energy. Traditionally, high thermoelectric figure-of-merit, ZT, has been the only parameter pursued for high conversion efficiency. Here, we emphasize that a high power factor (PF) is equivalently important for high power generation, in addition to high efficiency. A new n-type Mg2Sn-based material, Mg2Sn0.75Ge0.25, is a good example to meet the dual requirements in efficiency and output power. It was found that Mg2Sn0.75Ge0.25 has an average ZT of 0.9 and PF of 52 μW·cm-1·K-2 over the temperature range of 25-450 °C, a peak ZT of 1.4 at 450 °C, and peak PF of 55 μW·cm-1·K-2 at 350 °C. By using the energy balance of one-dimensional heat flow equation, leg efficiency and output power were calculated with Th = 400 °C and Tc = 50 °C to be of 10.5% and 6.6 W·cm-2 under a temperature gradient of 150 °C·mm-1, respectively.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 2015 Mar 17|
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