A team of researchers in China has created the first rubber band capable of converting body heat into electricity. The development could eliminate the need for charging in wearable devices such as smartwatches, fitness trackers, and medical sensors.
The new material combines elasticity with thermoelectric efficiency. By blending semiconducting polymers with elastic rubber and engineering a nanofiber network, the researchers achieved high conductivity and extreme stretchability—up to 850 percent of its original length—while maintaining its shape and performance. Special additives further improved its ability to convert temperature differences into usable power.
The concept builds on thermoelectric principles, where the difference between body temperature (around 37°C) and ambient conditions (20–30°C) can generate electricity. Unlike conventional thermoelectric materials, which are either rigid or lose function when stretched, this “thermoelectric rubber” remains durable, flexible, and efficient.
Potential applications extend beyond wearables. The material could be integrated into clothing to charge mobile devices and regulate body temperature, or into medical equipment where long-term monitoring currently requires large batteries. It may even be used in remote settings to power communications gear using heat sources like open fires.
This innovation points toward a future of self-powered electronics that are soft, comfortable to wear, and capable of producing energy indefinitely under normal conditions.
Original Story: Chinese scientists’ discovery may pave the way for self-charging smartwatches | South China Morning Post
