Researchers at Queensland University of Technology (QUT) have developed an ultra-thin, flexible film capable of converting body heat into electrical energy. This breakthrough could revolutionize wearable technology, offering a sustainable way to power devices without batteries.
Flexible Thermoelectric Film Technology
The new flexible thermoelectric film technology developed at QUT addresses longstanding challenges in the field, including limited flexibility, complex manufacturing, and high costs. The innovation combines bismuth telluride with tellurium nanorods to create a flexible, efficient film.
Bismuth telluride is a well-known thermoelectric material but struggles with rigidity. To overcome this, the QUT team added tellurium nanorods as “nanobinders,” which fill the gaps between bismuth telluride sheets, enhancing both flexibility and performance. This structure allows the film to effectively convert heat into electricity.
Figure: Such Wearables Can Change the Traditional Concept of Charging
What Are the Applications?
This flexible thermoelectric film has wide-ranging applications beyond wearable technology. It can also be used to cool electronic chips in smartphones and computers, improving their efficiency. For instance, when applied inside a device, the film can reduce chip temperatures by up to 11.7 Kelvin.
Wearable technology could benefit significantly from this advancement. By converting the temperature difference between the human body and the surrounding environment into electricity, these films could power self-sufficient wearable devices, eliminating the need for batteries. Professor Zhi-Gang Chen, who led the research, explains, “Flexible thermoelectric devices can be comfortably worn on the skin, turning body heat into electricity effectively.”
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Overcoming Manufacturing Challenges
Despite the promising potential, several challenges have impeded the development of flexible thermoelectric devices. These include limited flexibility, complex manufacturing processes, high costs, and performance limitations. The QUT team’s method integrates solvothermal synthesis, screen-printing, and sintering techniques to produce high-performance films cost-effectively. Solvothermal synthesis creates nanocrystals in a solvent under high temperature and pressure, screen-printing allows for large-scale production, and sintering binds particles together.
The team’s innovation is a printable film made from Bi₂Te₃-based nanoplates and Te nanorods, with high orientation of grains for optimal power density. This makes it one of the most efficient flexible thermoelectrics available.
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Performance Evaluation
The research team tested the film’s performance by creating a small-scale generator using an A4-sized sheet of the flexible film. The generator produced 1.2 milliwatts of power per square centimeter with a temperature difference of 20 Kelvin between the skin and the surrounding air. This level of power generation is readily achievable under typical ambient conditions, demonstrating the film’s potential for powering a variety of wearable devices.
Professor Chen highlights, “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.”
Beyond Wearables: Further Applications
The implications of this technology extend beyond wearables. The team also demonstrated its ability to cool electronic chips effectively. By converting energy reversibly, they achieved a temperature reduction of 11.7 Kelvin, which can help maintain optimal performance in electronic devices.
This film’s flexibility also opens up new possibilities in confined spaces, such as inside computers or mobile phones, where cooling chips can enhance performance. The QUT team envisions these flexible thermoelectric devices being applied to a wide range of applications, from smart clothing to automotive components.
What’s Next?
While the current research shows great promise, further research and development are necessary to scale up this technology and optimize its performance. The QUT team acknowledges that the journey to commercialization will require addressing remaining challenges, including durability, integration with existing devices, and cost-efficiency at scale.
Professor Chen remains optimistic about the future of flexible thermoelectric devices: “This flexibility in materials shows the wide-ranging possibilities our approach offers for advancing flexible thermoelectric technology.” With continued development, these devices could revolutionize energy efficiency in various sectors, from consumer electronics to automotive and medical applications.
