American researchers have identified a metal that conducts electricity without conducting heat. An incredibly useful property that challenges our current understanding of how conductive materials work.
The surprising properties of vanadium dioxide
Featured in the journal Science, the metal in question contradicts the Wiedemann-Franz law, which states that good conductors of electricity are proportionately good conductors of heat. Usually, motors and appliances tend to heat up when used regularly, which is not the case with vanadium dioxide (VO2), a material already renowned for its strange ability to switch from insulation to conductor status at a temperature of 67 ° C. For Junqiao Wu, lead author of the study, it is “ a discovery of fundamental importance for understanding the basic electronic behavior of new drivers “.
This discovery not only changes the way we think about conductive materials, but could prove to be incredibly useful as well: metal could one day be used to convert waste heat from motors and appliances into electricity, or even create sidings and windows that allow for ” effectively insulate buildings, winter and summer. While there are a handful of other materials that conduct electricity better than heat, these only exhibit such properties at temperatures several hundred degrees below zero, making their applications in the real world. hardly possible, unlike vanadium dioxide.
Surprisingly, the researchers found that the thermal conductivity that could be attributed to the electrons present in the material was 10 times lower than that predicted by the law of Wiedemann-Franz. This seems to be explained by the fact that the latter move in the material in a perfectly synchronized way. As explained Junqiao Wu : ” The electrons moved homogeneously, much like a fluid, instead of moving in disparate ways, as is the case with normal metals. The coordinated movement of electrons in vanadium dioxide drastically limits heat transfer. “
Interestingly, the researchers found that by mixing vanadium dioxide with other materials, such as tungsten, they could ” adjust »The amount of electricity and heat it could conduct, which could prove extremely useful in future applications. Using such alloys could in particular help to dissipate the heat of an appliance, by only conducting heat above a certain temperature threshold.
While there is still a lot of research to be done before this innovative material can be produced and used on a large scale, its amazing properties could enable major breakthroughs in many areas of the industry in the years to come.