A University of Liverpool-led team of scientists has discovered a new inorganic material offering the lowest thermal conductivity ever.
According to the team led by Liverpool professor Matt Rosseinsky and Dr Jon Alaria, the discovery represents a major breakthrough in the control of heat flow at the atomic scale and could pave way for new thermoelectric devices that harvest waste heat and also act as thermal barrier coatings for gas turbines.
Rosseinsky and Alaria designed and synthesized the new material which combines two different arrangements of atoms that are each found to slow down the speed at which heat moves through the structure of a solid.
Combining these mechanisms in a single material was however no easy task; they needed to control how the atoms are arranged within it.
The scientists chose favorable chemical interfaces between each of these different atomic arrangements to experimentally synthesize a material that combines them both.
Once this was done, they noticed that the new material with two combined arrangements had a much lower thermal conductivity than either of the parent materials with just one arrangement.
To illustrate with an example, if we take the thermal conductivity of steel as 1, then a titanium bar is 0.1, water and a construction brick is 0.01, the new material is 0.001 and air is 0.0005.
“The material we have discovered has the lowest thermal conductivity of any inorganic solid and is nearly as poor a conductor of heat as air itself,” notes Rosseinsky.
“The implications of this discovery are significant, both for fundamental scientific understanding and for practical applications in thermoelectric devices that harvest waste heat and as thermal barrier coatings for more efficient gas turbines.”
Alaria says that beyond heat transport, this strategy could be applied to other important fundamental physical properties such as magnetism and superconductivity, leading to lower energy computing and more efficient transport of electricity.
Image and content: University of Liverpool