Researchers have made a rubber band that can convert body heat into electricity, opening up possibilities for automatically charging wearable devices. The new material combines elasticity with efficient thermoelectric conversion, potentially eliminating the need for frequent charges or bulky batteries.
Thermoelectric Rubber Band
“Until now, all reported high-performance thermoelectric materials have realised only flexibility, rather than elasticity,” the researchers wrote.
According to thermoelectric principles, differences in temperature can generate power. Using this idea, scientists are attempting to extract power from the small difference in temperature between the human body and the surrounding air.
Human body temperature typically remains around 98.6 Fahrenheit (37 degrees Celsius), while ambient air ranges from 68 to 86 Fahrenheit (20 to 30 degrees Celsius). The material uses this gradient to generate electricity, according to Interesting Engineering.
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Though thermoelectric materials are nothing new, they’re difficult to create, as most materials are either too stiff or lose performance when stretched. The research team wanted to create a flexible material that could stretch, bend, and adhere to skin.
Lei Ting, a materials scientist at Peking University and the corresponding author, stated to SCMP. “We are the first in the world to propose the concept of thermoelectric rubber.”
“Such thermal devices are comfortable to wear and efficiently convert the body’s heat energy into electrical energy with less heat loss,” he added.
By mixing semiconducting polymers and elastic rubber, the researchers created a nanofibre network that is both conductive and flexible. When stretched to 150 percent of its original length, the material recovered over 90 percent of its shape compared to natural rubber.
Researchers also noted applications for the technology that go beyond wearables. For example, it could obtain power from heat generated by a fire or be integrated into clothing. If the material remains undamaged, researchers stated it could supply power indefinitely.
