New fabric uses sun, wind energy to power devices

A cloth fluttering in the wind on a sunny day could charge your phone in the future, thanks to a new fabric developed by scientists that can harvest energy from the Sun and wind.
Combining two types of electricity generation into one textile paves the way for developing garments that could provide their own source of energy to power devices such as smart phones or global positioning systems.
"This hybrid power textile presents a novel solution to charging devices in the field from something as simple as the wind blowing on a sunny day," said Zhong Lin Wang, Professor in the Georgia Institute of Technology in the US.

To make the fabric, researchers used a commercial textile machine to weave together solar cells constructed from lightweight polymer fibres with fibre-based triboelectric nanogenerators.
Triboelectric nanogenerators use a combination of the triboelectric effect and electrostatic induction to generate small amount of electrical power from mechanical motion such as rotation, sliding or vibration, scientists said.
The new fabric, which is 320 micrometres thick woven together with strands of wool, could be integrated into tents, curtains or wearable garments, Wang said.

"The fabric is highly flexible, breathable, light weight and adaptable to a range of uses," he added.
Fibre-based triboelectric nanogenerators capture the energy created when certain materials become electrically charged after they come into moving contact with a different material, researchers said.

For the sunlight-harvesting part of the fabric, they used photoanodes made in a wire-shaped fashion that could be woven together with other fibres.
"The backbone of the textile is made of commonly-used polymer materials that are inexpensive to make and environmentally friendly," Wang said.
"The electrodes are also made through a low cost process, which makes it possible to use large-scale manufacturing," he added.
In one of the experiments, the team used a fabric only about the size of a sheet of office paper and attached it to rod like a small colourful flag.
Rolling down the windows in a car and letting the flag blow in the wind, the researchers were able to generate significant power from a moving car on a cloudy day.

The researchers also measured the output of a 4x5 centimetre piece, which charged up a commercial capacitor to two volts in one minute under sunlight and movement.
"That indicates it has a decent capability of working even in a harsh environment," Wang said.
While early tests indicate the fabric can withstand repeated and rigorous use, researches will be looking into its long-term durability.
The research appears in the journal Nature Energy.