New York - If allowing your smartphone to run out of power during the day doesn’t make you feel silly enough, consider this: Every hour it’s idle in your pocket or bag, the sun is bathing the earth in enough energy to run the world economy for a year.
The obvious fix here is to turn every square inch of your body into a power plant—solar could be the ultimate accessory, more important than purses, satchels, or, well, sunglasses. But first, there’s the science part.
Wearable technology has been largely constrained to the sartorial periphery—smartwatches, camera-sunglasses, and fitness trackers. Much of the fabric tech in the apparel industry is devoted to things needed for activewear and workout gear: moisture-wicking, stretchiness, breathability. Smart garments have popped up here and there, mostly dealing with athletics and personal care. Ralph Lauren, Hexoskin, and Athos all make shirts that record biometric data, such as heart and breathing rates. That’s pretty much it.
But beyond all the fancy gadgetry, there’s a much simpler melding of clothing and energy. Fashion labels have long sought to lure shoppers with clothes and accessories that can charge phones. Michael Kors even made chargers disguised as lipstick tubes. Tommy Hilfiger developed a line of jackets with solar panels. Kate Spade sold phone-charging handbags. All need to be recharged via plug or mat. A flexible, lightweight fabric that can harvest energy from the sun may appeal to labels chasing the on-the-go shopper, especially in urban centers where there is more walking and less driving.
Holdup
The main holdup may not even be the most obvious—shrinking a power plant down to pocket-size. The trouble is coming up with electronics that can 1) be cut and sewn together like regular fabric and 2) work the same in all designs and sizes, without compromising its energy profile. It’s up to the scientists to deliver, and a few in China claim that they've gotten a little closer to making it work.
A team of researchers have said they developed a fabric that’s made from cotton and two advanced electronic fibers. One fiber generates power from sunlight, and the other, called a “fiber supercapacitor,” stores the electrons and provides current, like a battery. The scientists say their fiber can withstand the bending, twisting, and wrapping normal to industrial weaving, a critical area in smart-fabrics research. Fixing rips in the fabric isn’t as easy as ironing on a new patch—connecting a new swatch into a garment represents a “delicate sewing process,” according to the new study, published in the journal ACS Nano.
The material has been tested at light intensities between 70 percent and 120 percent of the sun's average, and works in natural and artificial light, according to Wenjie Mai of Jinan University. The researchers are in touch with a few Chinese companies, he said.
The new techniques let them weave solar fibers and power storage into “many possible patterns and tailor them into any designed shape without losing their performance,” wrote the authors, led by Zhisheng Chai, also of Jinan University. “This breakthrough makes it possible to produce stylish smart energy garments with enhanced user experience and more room for fashion design.”
The research was funded by the National Natural Science Foundation of China, the Natural Science Foundation of Guangdong province, China, and the Program for New-Century Excellent Talents in University.
While light-harvesting clothing sounds as if it’s within reach, there are some practical problems that won’t be easily overcome. For one, the wired fabric isn't waterproof yet.
The sun doesn’t always shine and the wind doesn’t always blow, making these only intermittent fuels—a problem the renewable energy industry knows well. Intermittent energy may pose a compound problem for the bright new world of solar clothing: In summer, when daylight is longest and the temperature is hot, people wear sleeveless T-shirts and shorts.
This means less surface area, less power, and—in the end—your phone may still die before you’ve left the beach.
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