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Tohoku Univ. Technology
Admin No.T20-338

Mg2Si thermoelectric conversion film with reduced thermal conductivity while keeping electrical conductivity

Mg2Si film with high porosity and uniform vacancies

Overview

 The development of thermoelectric conversion technology to extract electricity from waste heat is being actively pursued. Mg2Si is a thermoelectric conversion material suitable for the use of industrial waste heat since the thermoelectric conversion efficiency achieves its maximum value at around 300ºC environment.
 However, the heat is often leaked due to its high thermal conductivity so the conversion efficiency is not as high as expected (cf. right formula). There is a report that the thermal conductivity was decreased by compacting Mg2Si powder into pellet and making it porous, but since the electrical conductivity was also reduced due the grain boundary, the conversion efficiency was not increased.
 This invention is about a Mg2Si porous film that solves the above issue.

Mg2Si thermoelectric conversion film with reduced thermal conductivity while keeping electrical conductivity

Low thermal conductivity by honeycomb-like highly porous film

Mg2Si thermoelectric conversion film with reduced thermal conductivity while keeping electrical conductivity

Product Application

 The present porous Mg2Si film shows the same electrical conductivity (~2 S/cm) as an ordinary Mg2Si thin film such as sputtered film, but the thermal conductivity is reduced by 11% even with a single porous structure layer. Therefore, it is possible to realize a thermoelectric conversion device by increasing film layers with less thermal leakage in the waste heat range around 300ºC.

Related Works

[1] Chem. Mater. 2020, 32, 10176.

IP Data

IP No.  : JP2020-145374
Inventor : YAMADA Takahiro, YABU Hiroshi, MATSUI Jun
keyword : Environment, Energy







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