Picture wearing a simple rubber band on your wrist that powers your smartwatch just from your body heat. That’s no longer science fiction. Researchers at Peking University have developed the world’s first thermoelectric rubber band, capable of generating electricity from the temperature difference between your skin and the surrounding air, as reported by The SCMP.
The material is built by weaving semiconducting polymers into elastic rubber, creating a nano-fiber network that conducts electricity while still stretching like normal rubber. It can expand to more than eight times its original length and spring back almost perfectly, which is unusual for something designed to move electrons efficiently. The researchers also added a doping agent that boosts its thermoelectric performance at room temperature, a critical step that makes it viable for daily use.
Why does this matter? Because it could completely change how we power wearables and small devices. Instead of charging a smartwatch or a medical sensor with cables or disposable batteries, the rubber band could keep them running continuously using nothing more than your body heat. Imagine clothing that charges your phone as you walk, or health monitors that never need recharging.
The potential applications don’t stop there. In healthcare, the band could be built into lightweight monitors that track cardiovascular health without relying on batteries that eventually run out. Outdoors, it could even be integrated into gear for hikers or emergency workers, producing electricity from body warmth when other power sources aren’t available. Engineers are also considering how it could be used in fabrics for smart clothing, both for comfort and for powering electronics on the go.
What makes this breakthrough especially exciting is how natural it feels. Unlike bulky chargers or batteries, a simple rubber band that stretches, flexes, and works without interruption fits seamlessly into daily life. It represents a step toward self-sustaining electronics—gadgets that don’t constantly need to be plugged in, but instead run off the most reliable source we have: our own bodies.
This invention may be small in size, but its implications are big. If it scales up, the way we think about charging devices could change forever.
