Invisibly minute carbon nanotubes, drawn as fibers and sewn into fabrics, turn out to be a thermoelectric generator that can convert heat from the sun or other sources into energy.
Physicist Junichiro Kono from Rice University laboratory guided a team of scientists at Tokyo Metropolitan University (TMU) and the Rice-based Carbon Hub to develop tailored nanotubes and test their potential for large-scale applications.
The small-scale experiments of the researchers resulted in a fiber-improvised, flexible cotton fabric that converted heat into required energy to power an LED. Further improvements will enable the materials to form building blocks for fiber and textile electronics and energy harvesting. The same nanotube fibers can find application as heat sinks to actively cool sensitive devices with greater efficiency.
The study has been published in the journal Nature Communications.
The effect looked to be simple, where, if one side of thermoelectric material is hotter compared to the other, it generates energy. The heat may arrive from the Sun or other devices such as the hotplates that are employed in the fabric experiment. In another way, adding energy can encourage the material to cool the hotter side.
So far, macroplastic assemblies of nanomaterials have not displayed the required, “giant power factor” of around 14 mW/mK2. This is the value quantified by the Rice researchers in carbon nanotube fibers.
The power factor tells you how much power density you can get out of a material upon certain temperature difference and temperature gradient.
Natsumi Komatsu, Study Lead Author and Graduate Student, Rice University