A battery-free fiber illuminates textiles

In the new sci-fi movie Dune: Part Two, most everyone traveling into the desert of the planet Arrakis wears a stillsuit. It uses energy from the motion of its wearer to distill sweat into water. But in real life, many wearable electronics, such as smartwatches, require silicon-based microprocessors, wires, and batteries to function. Clothing embedded with such components is stiff, uncomfortable, and reliant on a battery or another power source.

A newly developed electronic fiber could overcome many of those obstacles. Designed by Qinghong Zhang, Chengyi Hou, and Hongzhi Wang of Donghua University in Shanghai, China, and their colleagues, the fiber is flexible enough to be comfortably woven into clothing and other textiles, and it doesn’t require an external power source or any computer chips. Instead, it stores and disperses energy that it draws with the help of the human body.

The new fiber has three concentric layers—an antenna core that induces an electromagnetic field, a middle layer for energy storage, and an optical layer. Most of the electrical energy from cell phones, power cables, fabric friction, and other ambient sources dissipates in air because of air’s high electrical impedance. The human body has a lower impedance. So, when a person’s skin touches the fiber, a contact capacitance forms and creates a closed energy loop. Electrical energy in the surrounding air is guided preferentially through the body to the fiber and eventually the ground. The transmitted energy powers the antenna core’s electromagnetic field. Then the middle layer confines it, and the fiber transmits it to the optical layer to emit light.

The researchers have demonstrated many possible applications. They developed a fabric keyboard that can be used to type out messages onto a display embedded in clothing. And they showed how lights in a room turn on hands-free after a person’s feet touch a carpet woven with the electronic fiber. The researchers manufactured the fiber using some industrial-scale equipment and processes, which could prove useful if the technology is commercialized. (W. Yang et al., Science 384, 74, 2024 .)