Scientists from China’s Zhejiang University have developed a reversible textile which traps warmth in the cold and reflects it during hot weather, generating small amounts of electricity simultaneously. The textile is easy and inexpensive to fabricate. This creates many possibilities such as clothing that generates electricity to power wearable electronics.

Previous attempts to develop such sophisticated textiles for outdoor use have generally focused on either capturing thermal radiation or dispersing it. To integrate the two, Qiang Li, Min Qiu and colleagues made a layered fabric made of porous fibrous polymers. To trap warmth in the cold, they coated the heating side in zinc and copper nanoparticles to absorb solar energy and keep in thermal radiation from the body. To release heat in the hot sun, they placed a hierarchically porous structure on the cooling side to reflect sunlight and dissipate human body radiation.

In the sun, the heating side increased a simulated skin’s temperature by as much as 14 F more than did black cotton. With the cooling side out, the textile dropped the temperature by 11 F compared to white cotton. In night tests, the heating side warmed the simulated skin by 5 F more than black cotton, but the cooling side did not result in a lower temperature. By attaching a small thermoelectric generator to the textile, the researchers could harness the temperature gradient between its inner surface and skin to produce a small amount of electricity.

They say the textile is easy and inexpensive to fabricate and has breathability comparable to cotton. This textile creates new possibilities for many technologies, such as multi-functional camouflage or clothing that can generate electricity to someday power wearable electronics, the researchers say.

The research was funded by the National Key R and D Programme of China and the National Natural Science Foundation of China.