Thermoelectric Materials, But Make it Fashion

Imagine a jacket that could convert body heat into power to charge a cell phone. Or, a coat that could serve as a wearable “air conditioner” on hot days, and on cold days, a wearable “heater.” 

To help make this a reality, Northwestern Engineering researchers have developed a new flexible, thermoelectric material that can be continually produced via 3D-printing and collected on a spool in ambient air. This finding is a critical step toward robust, wearable, and carbon-free energy-harvesting devices. 

“Expanding the applications of thermoelectric materials is urgent,” said Matthew Grayson, professor of electrical and computer engineering and coauthor of the paper published in Nature Communications. “Recent world events such as wildfires, floods, and epidemics are all consequences of global warming, making the departure from fossil-fuel energy sources all the more critical.” 

“In our research, the lateral compression of the thermoelectric threads proved to be a critical step to dramatically improve the electrical conductivity and overall performance of the composite.” said Jun Peng, first author on the paper and postdoctoral fellow of Grayson. 

The paper, “3D extruded composite thermoelectric threads for flexible energy harvesting,” was a collaboration between Grayson’s electrical transport group in the Department of Electrical and Computer Engineering, professor Jeffrey Snyder’s Thermoelectrics Group in the Department of Materials Science and Engineering, and startup company Dimension Inx.  

Previously, thermal energy harvesting was restricted to rigid platforms and wasn’t able to be to be easily worn.   

The fabrication method, Grayson said, is so simple and cheap, that it could be imagined in industrial-scale spools woven in textile mills into fabrics for thermal and energy management purposes.