In a groundbreaking development, researchers at the University of Washington (UW) have unveiled a cutting-edge, flexible electronic device that captures energy from body heat to generate electricity. This innovative prototype promises to power small electronics, ranging from sensors to LEDs, potentially transforming the wearable technology landscape.
The device, a brainchild of Mohammad Malakooti, an assistant professor of mechanical engineering at UW, embodies a vision he held for years. “When you put this device on your skin, it uses your body heat to directly power an LED. As soon as you put the device on, the LED lights up. This wasn’t possible before,” Malakooti shared, emphasizing the unprecedented capability of their creation.
Unlike traditional devices designed to generate electricity from heat, which typically are rigid and fragile, this new invention is remarkably flexible and durable. It can endure significant mechanical stress, remaining functional after being pierced multiple times and stretched up to 2,000 times, thereby ensuring reliability in everyday use.
The device’s core is ingeniously structured in three primary layers. At its heart lie rigid thermoelectric semiconductors adept at converting heat into electrical energy. These semiconductors are encased in 3D-printed composites with low thermal conductivity, optimizing energy conversion while lightening the device. To ensure the device’s stretchability, these semiconductors are connected with printed liquid metal traces, which also impart conductivity and self-healing properties.
Enhancing the device’s efficiency are outer layers embedded with liquid metal droplets, which bolster heat transfer to the semiconductors while maintaining flexibility. This unique feature allows the metal to remain liquid at room temperature, further facilitating the energy conversion process. Every component, except the semiconductors, was meticulously designed and fabricated in Malakooti’s lab.
Malakooti sees a wealth of applications beyond wearables for this transformative technology. One intriguing potential is in cooling and power management within data centers. “You can imagine sticking these onto warm electronics and using that excess heat to power small sensors,” Malakooti explained. In data centers, this could mean capturing the heat generated by servers to power temperature and humidity sensors—an approach that not only boosts sustainability by repurposing waste heat but also reduces the need for additional power sources, thus lowering overall energy consumption.
Additionally, the device holds promise for reverse applications—using electricity to generate heating or cooling. This could one day enhance virtual reality systems and other wearable technologies, creating tactile thermal sensations or providing varying degrees of comfort. “We’re hoping someday to add this technology to virtual reality systems and other wearable accessories to create hot and cold sensations on the skin or enhance overall comfort,” Malakooti suggested. Although this future vision is still on the horizon, the team’s current focus is on perfecting durable wearables that offer reliable temperature feedback.
This pioneering research benefited from the contributions of Youngshang Han, a doctoral student in mechanical engineering at UW, and Halil Tetik, who now serves as an assistant professor at the Izmir Institute of Technology after his postdoctoral work at UW. Both Malakooti and Han are associated with the UW Institute for Nano-Engineered Systems. The project received generous support from the National Science Foundation, Meta, and The Boeing Company, underscoring the high-impact potential of this innovative technology.
This leap forward suggests a future where our devices could draw power from our own bodies, mitigating concerns about battery life and elevating the scope of wearable technology to new heights.