Researchers created a custom carbon nanotube that can be sewn in fabric and can convert heat into electricity efficiently.
Thermoelectric effect has been extensively studied by the researchers due to emerging battery-less technologies. The effect is very simple: if one side of thermoelectric material is hotter than the other, there is a charge imbalance between the two sides of the material. The heat can be anything like sun or hotplates.
Recent studies have shown that carbon nanotubes aligned as fibers can turn heat from the sun or other sources into energy. Researchers from Rice University lab of physicist Junichiro Kono along with Tokyo Metropolitan University and the Rice-based Carbon Hub have created a custom nanotube and tested its potential for fairly large scale applications.
They found out that small-scale fiber-enhanced, flexible cotton fabric that turned heat into enough energy to power an LED. The nanotubes can also be used as heat sinks to actively cool sensitive electronics with high efficiency. The developed custom nanotubes demonstrated a power factor of around 14 milliwatts per meter kelvin squared.
“The power factor tells you how much power density you can get out of a material upon a certain temperature difference and temperature gradient,” said Rice graduate student Natsumi Komatsu, lead author of the paper. According to her, the increased power factor is due to electrical conductivity of the material and the enhanced Seebeck coefficient which measures how much heat energy is converted into electricity.
“The ultrahigh electrical conductivity of this fiber was one of the key attributes,” Komatsu said.
“Carbon nanotube fibers have been on a steady growth path and are proving advantageous in more and more applications,” Pasquali, Director of the Carbon Hub, said. “Rather than wasting carbon by burning it into carbon dioxide, we can fix it as useful materials that have further environmental benefits in electricity generation and transportation.”
“Nanotubes have been around for 30 years, and scientifically, a lot is known,” he said. “But in order to make real-world devices, we need macroscopically ordered or crystalline assemblies. Those are the types of nanotube samples that Matteo’s group and my group can make, and there are many, many possibilities for applications.”
The researchers believe that their custom nanotubes could become building blocks for fiber and textile electronics and energy harvesting.
The research appeared in the journal Nature Communications.