Body heat tapped for power
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Queensland engineers are looking to power wearable devices with body heat.
A QUT-led research team has developed an ultra-thin, flexible film that could eliminate the need for batteries, offering a sustainable energy source for wearable electronics, as well as an efficient cooling method for chips.
The scientists behind the paper published in the journal Science says that the breakthrough tackles a major challenge in creating flexible thermoelectric devices that convert body heat into power.
“Flexible thermoelectric devices can be worn comfortably on the skin where they effectively turn the temperature difference between the human body and surrounding air into electricity,” said researcher Professor Zhi-Gang Chen.
“They could also be applied in a tight space, such as inside a computer or mobile phone, to help cool chips and improve performance.
“Other potential applications range from personal thermal management - where body heat could power a wearable heating, ventilating and air conditioning system.
“However, challenges like limited flexibility, complex manufacturing, high costs and insufficient performance have hindered these devices from reaching commercial scale.”
Most research in this area has focused on bismuth telluride-based thermoelectrics, valued for its ability to convert heat into electricity, making it ideal for low-power applications like heart rate, temperature or movement monitors.
In the latest study, the team introduced a cost-effective technology for making flexible thermoelectric films by using tiny crystals, or ‘nanobinders’, that form a consistent layer of bismuth telluride sheets, boosting both efficiency and flexibility.
“We created a printable A4-sized film with record-high thermoelectric performance, exceptional flexibility, scalability and low cost, making it one of the best flexible thermoelectrics available," Professor Chen said.
The team used “solvothermal synthesis”, a technique that forms nanocrystals in a solvent under high temperature and pressure, combined with “screen-printing” and “sintering”.
The screen-printing method allows for the large-scale film production, while sintering heats the films to near-melting point, bonding the particles together.
The technique could also work with other systems, such as silver selenide-based thermoelectrics, which are potentially cheaper and more sustainable than traditional materials.
