Turning textiles into power generators

November 01, 2024

Researchers have discovered a method to transform textiles into power sources. This means someday your sweater could charge your phone or monitor your health, all while you’re on the go. 
 
Scientists at Chalmers University of Technology in Sweden are bringing this vision closer to reality. 

They have developed a special silk thread coated with a conductive plastic material. This innovative thread can harness the power of body heat to generate electricity.

This flexible, lightweight, and non-toxic material makes it ideal for wearable applications.

Silk thread with conducting polymer
 
Thermoelectric textiles generate electricity from temperature differences, such as between your body and the environment. When combined with sensors, this technology can benefit us in numerous ways, from powering wearable devices to monitoring vital signs. Interestingly, it completely eliminates the use of batteries. 

The silk thread was coated with a conducting polymer, a plastic material with a unique chemical structure that allows for electrical conductivity. 
 
“The polymers that we use are bendable, lightweight and are easy to use in both liquid and solid form. They are also non-toxic,” said Mariavittoria Craighero, the first author and a doctoral student at the university.  
 
To demonstrate the practical application of the new thread, the researchers created two thermoelectric generators: a button and a piece of fabric with threads.  
 
When these devices were exposed to a temperature difference, they generated electricity. The amount of voltage produced varied based on the temperature difference and the quantity of conductive material present. 
 
The bigger the temperature difference, the more power the textile generated. 
 
The larger fabric produced approximately 6 millivolts at a 30-degree temperature difference. Combined with a voltage converter, it could potentially charge portable devices via USB. 
 
The thread is washable
 
Interestingly, the thread remained effective for over a year and can withstand multiple washes without losing its electrical conductivity.

“After seven washes, the thread retained two-thirds of its conducting properties. This is a very good result, although it needs to be improved significantly before it becomes commercially interesting,” said Craighero.

Currently, the thermoelectric fabric and buttons are challenging to produce efficiently outside of a lab setting. They require manual labor for both material creation and sewing. For instance, sewing a single fabric took four days.  
 
However, researchers believe that the new thread has significant potential and that automating the process could enable large-scale production. 
 
“We have now shown that it is possible to produce conductive organic materials that can meet the functions and properties that these textiles require,” said Christian Müller, the lead researcher from the university, in the press release. 
 
This is an important step forward. There are fantastic opportunities in thermoelectric textiles and this research can be of great benefit to society.” 
 
By converting temperature differences into electrical energy, these textiles can power a range of wearable devices, from fitness trackers to medical sensors.

The field of smart textiles has seen considerable advancements in recent years. Another recent exciting development came from the University of Waterloo, where researchers unveiled a new smart fabric. 
 
The team combined MXene and conductive polymers with innovative textile techniques to create stretchable thermoelectric fabric.