Chinese scientists develop rubber band that powers devices using body heat
By isabelle // 2025-09-04
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  • Scientists at Peking University have developed a stretchable rubber-like material that converts body heat into electricity for wearable tech.
  • The thermoelectric elastomer generates power from the temperature difference between skin and air, eliminating the need for batteries.
  • It can stretch up to 150% and withstand extreme strain without losing functionality, making it ideal for skin-tight wearables.
  • Potential applications include self-powered smartwatches, medical monitors, and clothing that charges devices using body heat.
  • This breakthrough could reduce dependency on corporate charging infrastructure and empower individuals with energy autonomy.
Can you imagine a world where your smartwatch never needs charging, your medical monitor runs indefinitely without batteries, and your fitness tracker draws power simply from the warmth of your skin? That future may be closer than you think. A team of researchers at Peking University has just unveiled a revolutionary rubber-like material that converts body heat into electricity in an innovation that could finally free wearable technology from the tyranny of batteries and charging cables. The breakthrough, published in the journal Nature, introduces a thermoelectric elastomer—a stretchable, conductive polymer that generates power by harnessing the natural temperature difference between your body (around 37°C) and the cooler surrounding air. Unlike rigid thermoelectric materials used in space probes or industrial applications, this new rubber can stretch up to 150% of its original length and recover its shape, making it ideal for skin-tight wearables. Even more impressive, it can withstand extreme strain of over 850% without losing functionality.

How does it work?

The science behind this innovation lies in thermoelectricity, the process where a temperature gradient between two points creates an electrical current. Your body is a constant heat source, maintaining a steady 37°C, while the air around you fluctuates between 20°C and 30°C. The Peking University team’s material exploits this difference, allowing electrons to flow from the warmer side (your skin) to the cooler side (the air), generating usable electricity. To enhance performance, the scientists incorporated a doping agent called N-DMBI, which significantly boosts conductivity. The result? A material that not only stretches like rubber but also efficiently converts heat into power—something previous thermoelectric materials struggled to achieve. “We are the first in the world to propose the concept of thermoelectric rubber,” said Lei Ting, a materials scientist at Peking University, in an interview with the South China Morning Post. “Such thermal devices are comfortable to wear and efficiently convert the body’s heat energy into electrical energy with less heat loss.”

A game-changer for wearables and medical devices

The implications of this technology are vast. Currently, smartwatches, fitness trackers, and even medical monitors rely on bulky batteries that require frequent recharging. This new material could eliminate that need entirely, enabling self-powered devices that run indefinitely as long as they remain in contact with skin. But the applications don’t stop at consumer electronics. The researchers envision medical sensors that could be worn as patches, continuously monitoring patients without the hassle of battery replacements. For example, cardiovascular patients who currently wear cumbersome holter monitors for a week could instead use lightweight, flexible sensors powered by their own body heat. Lei Ting also suggested broader uses, such as integrating the material into clothing. Imagine a jacket that charges your phone while you walk or a shirt that regulates your body temperature by drawing heat outward. In emergency scenarios, devices could even scavenge heat from a fire to power remote communications gear. This breakthrough arrives at a critical time. For years, Big Tech has pushed consumers into an endless cycle of planned obsolescence with devices that degrade, batteries that fail, and upgrades that force you to buy new products. Meanwhile, the medical industry has increasingly relied on centralized, battery-dependent monitors that limit patient freedom and increase costs. A self-powered, stretchable energy source changes the game. It reduces dependency on corporate-controlled charging infrastructure and empowers individuals with true energy autonomy. No more being tethered to outlets. No more disposable batteries leaching toxins into landfills. Just clean, continuous power generated by the most reliable source we have: our own bodies.

Potential challenges

While the technology is promising, real-world implementation will require further testing. Durability over long-term use, scalability for mass production, and integration with existing electronics are all hurdles to overcome. However, the fact that this material can retain 90% of its shape after stretching to 150% suggests it’s already robust enough for practical applications. The researchers also noted that special doping agents could further enhance performance, potentially making the material even more efficient. If successful, this could lead to commercial adoption within the next few years, revolutionizing not just wearables but also implantable medical devices that currently rely on invasive battery replacements. This isn’t just about charging a smartwatch. It’s about redefining how we power our lives—without strings attached. Sources for this article include: TechXplore.com The-Independent.com InterestingEngineering.com
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