Un equipo de la Universidad de Pekín presenta la primera banda elástica termoeléctrica, que ofrece energía continua para wearables, equipos de comunicación remota y dispositivos médicos. Los generadores elásticos intrínsecamente
Chinese researchers have created the world’s first rubber band that converts body heat into electricity. The breakthrough could allow smartwatches and other wearable devices to charge automatically without bulky batteries or frequent charging.
The team said the material combines elasticity with efficient thermoelectric conversion, a combination not seen before.
“Until now, all reported high-performance thermoelectric materials have realised only flexibility, rather than elasticity,” the researchers wrote.
Body heat to power
The innovation builds on thermoelectric principles, where temperature differences generate power. The Watt steam engine once turned boiling water heat into motion. Now, scientists are trying to harness the smaller difference between the human body and the surrounding air.
Body temperature remains around 37 degrees Celsius (98.6 Fahrenheit), while ambient air usually ranges from 20 to 30 degrees Celsius (68 to 86 Fahrenheit).
The Chinese team developed a material that exploits this gradient to produce electricity.
Thermoelectric materials are not new. Space probes have long relied on radioactive isotopes to generate power where solar energy is unavailable. But most existing materials are either too rigid or lose performance when stretched.
Lei Ting, a materials scientist at Peking University and corresponding author, explained the novelty to SCMP. “We are the first in the world to propose the concept of thermoelectric rubber,” he said.
Lei said his team wanted a material that could bend, stretch and cling to skin. “Such thermal devices are comfortable to wear and efficiently convert the body’s heat energy into electrical energy with less heat loss,” he added. He said that in theory the material would continue to supply power indefinitely if it remained undamaged.
The advance comes from blending semiconducting polymers with elastic rubber. The researchers engineered a nanofibre network to achieve both stretchability and conductivity.
After treatment, the material stretched to more than 850 percent of its original length. When stretched to 150 percent, it recovered over 90 percent of its shape, comparable with natural rubber.
Special doping agents boosted its performance further. These dopants created room-temperature thermoelectric properties that rival conventional inorganic materials.
This development marks progress in n-type elastomers, referring to materials that conduct electrons and maintain conductivity under mechanical strain. Until now, achieving elasticity alongside high electrical output in n-type systems had remained elusive.
Wider applications
Lei told SCMP that the research is not limited to charging wearables. “This isn’t just about charging wearables,” he said, noting possible uses in remote communications. For example, devices could draw power from heat generated by a fire.
The group also aims to integrate the rubber into clothing. Such garments could charge a phone in a pocket while using semiconductor wires to move body heat outward and regulate temperature.
Medical applications are another focus. Cardiovascular patients often wear monitoring devices for a week, which require large batteries. The new material could replace those with lightweight sensors that draw power directly from body heat.
