Researchers at the University of Washington develop wearable thermoelectric device. The device is intended to power wearable electronics such as smart watches and virtual reality headsets.

Publishing their findings in July this year, the team, led by master’s student Youngshang Han, claims that the efficient device is soft and stretchable while remaining sturdy.  

When compared with earlier stretchable, thermoelectric generators, the prototype showed a 6.5x increase in power density.

The team is combatting the limitations of these early devices, namely stretch inability, inefficiency of heat transfer and the complexity of the fabrication process. Designing the 3D printed composites with specific structural arrangement to increase functionality allows improved stretchability. Meanwhile, the liquid metal alloys contained within the filler material provide more efficient heat transfer due to their high electrical and thermal conductivity. To reduce device weight and direct heat to the semi-conductors the material also has embedded microspheres.

Remaining fully functional through testing of 15,000 stretching cycles at 30% strain the researchers believe the device could be printed on stretchable textile fabrics and curved surfaces. This allows for real-life application within clothing and other objects.

Of the design process, Mohammad Malakooti, a University of Washington assistant professor of mechanical engineering, says “one unique aspect of our research is that it covers the whole spectrum, all the way from material synthesis to device fabrication and characterisation […] this gives us the freedom to design new materials, engineer every step in the process and be creative.”