Weaving Batteries And Solar Cells Into Textiles
IRA FLATOW, host:
This is SCIENCE FRIDAY from NPR. I'm Ira Flatow.
Perhaps for the holidays, you got - did you get some high-tech clothing, a jacket where your iPhone fits, maybe gloves built in with those speaker-microphones? But what if the clothes were the devices themselves, like your polo shirt doubling as a battery pack, each thread a tiny, flexible lithium battery.
Well, my next guest may have figured out one of the secrets to get us closer to these futuristic fabrics, a way to take all kinds of material, I mean batteries, solar cells, superconductors, and twist them into tiny yarns that could be woven into fabric. That work appears this week in the journal Science.
Ray Baughman is director of the NanoTech Institute at the University of Texas at Dallas and professor of chemistry there. Welcome to SCIENCE FRIDAY.
Dr. RAY BAUGHMAN (Director, NanoTech Institute, University of Texas at Dallas): Oh, thank you. It's a great honor to be on NPR. I listen to it all the time.
FLATOW: Thank you very much. Tell us what you - about these fibers and how you make them and what you put in them.
Dr. BAUGHMAN: Okay, ordinary yarns are functional. You know, since prehistoric times, humankind has used yarns to make textiles to provide protection and beauty. Now, as - we want to make textiles from yarns that are multifunctional. And what we put into the yarns determines this extra function, whether it be energy harvesting, energy storage or energy conversion or even superconductivity.
FLATOW: So you make the yarns functional by what's inside the yarn.
Dr. BAUGHMAN: And powders are especially important for providing functionality. A challenge in the past is: How do you take powders and make them into yarns that are mostly powder without destroying the ability to knit, sew, weave and braid the yarn. This is the type of problem we solved.
FLATOW: And tell us what kinds of things you could make. I mean, what are the powders made of that you twist into these yarns?
Dr. BAUGHMAN: We use - for example, to make superconducting yarns, we use a mixture of magnesium and boron in order to make the superconductor.
The fundamental approach, however, is that we take webs of carbon nanotubes. These are little cylinders of carbon. These webs are an unusual state of matter in the sense that they can be lighter than air but still stronger than - on a per-weight basis, than steel.
We take these carbon nanotube webs and overlay them with powders of the guest material so that we make a yarn eventually that is 95 percent, or even more, of powder.
FLATOW: So the yarn just gives it a shape.
Dr. BAUGHMAN: The yarn gives strength because of the - and shape because of the extremely high mechanical properties of the individual carbon nanotubes, they're able to - a few percent of these carbon nanotubes is able to hold together this vastly larger amount of powder.
FLATOW: So if you - if the powder is made up, let's say, of battery material, and you put it into the yarn, the yarn now just becomes a big battery.
Dr. BAUGHMAN: It becomes a battery electrode, and we can make - take another yarn, which is the opposite electrode, and twist those two yarns together with a ionically electronically insulating material in between, and we get a battery.
FLATOW: So your shirt could be a battery.
Dr. BAUGHMAN: Yeah, even more than that. The individual fibers in your short can be individual batteries.
FLATOW: You don't want to get wet.
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Dr. BAUGHMAN: That's not really a problem because these batteries, the yarns, will be overcoated in such a way that you can't get shorts.
FLATOW: But, you know, thinking of clothing, but you could make furniture, for example, or car seats and things that could store electricity in them or...
Dr. BAUGHMAN: You're right on the mark. We can - for example, in automobiles, there's a major effort from a viewpoint of saving energy to make the cars lighter. On the other hand, people want to have electrical vehicles where you harvest the energy from braking to power the car at later times. So you want to have a battery or supercapacitor in the car.
But batteries and supercapicitors add a lot of weight. If you want to minimize the amount of weight that results, you can just make - weave these sort of yarns, a fabric, which is placed in the panel of the automobile, which provides strength for the automobile but also provides the ability to store electricity.
FLATOW: Could you make the car itself, the body out of, you know, you have carbon bodies, right. Could you just weave it out of a carbon fabric and store the electricity right in the fender?
Dr. BAUGHMAN: You're absolutely right. The - again, thinking - a lot of our work, most of our work in this new technology was supported by the Air Force. The Air Force is interested in having air vehicles and micro-air vehicles that are light, that have longer range. And there we're talking about having the whole framework of the aircraft be made out of these special multifunctional yarns that provide strength plus also functions, even the ability, for example, in a micro-air vehicle to morph the wing.
FLATOW: What about storing hydrogen, for example?
Dr. BAUGHMAN: Ah, that's a good question also. A major problem with conventional hydrogen storage material is that there are powders that break apart when you cycle hydrogen in and out.
And there's no real way to get hydrogen in and out of a container of a powder because you have to diffuse through large distances. But if we incorporate our powders for our yarns into these particular geometries that we use, you have -you hold the particles in place. So when they break apart, that doesn't matter. And you can provide a woven, vascular system of the yarns that allows easy entrance of the hydrogen and exit of the hydrogen.
These powders in our multifunctional yarns are held together in the corridors of scrolls. Think of your bath - rubberized bathroom mat for the shower. If you twist this mat into a rod by twisting from one side, you get what's called an Archimedean scroll. If you twist another way, you get more complex scrolls.
But in each case, the scroll enables the powder to be trapped, so much trapped that we can take our multifunctional yarns, weave them into textiles, wash them vigorously, and we see no change in their properties.
FLATOW: Wow. Let me get a quick question from Alicia(ph) in Mesa, Arizona. Hi.
ALICIA (Caller): Hi. I was wondering if these fibers can be used to heat and cool our bodies in indoor environments, and I'm also wondering about therapeutic applications. I'm a nurse. I'm wondering about keeping neo-nat's bodies at a particular temperature after birth and keeping people cool during surgical procedures and that sort of thing.
Dr. BAUGHMAN: Oh, very good question. The - because the yarns are electric conducting, we could heat textiles electrically. But you could do this with an ordinary metal wire.
More interestingly is we can use multifunctionality to be able to change the porosity of a textile. And that enables heat, for example, for a soldier who's in a hot environment or exercising, that heat and perspiration to evaporate. On the other hand, if he's in a cold, or he or she is in a cold environment, you can close the pore structure of the textile.
Dr. BAUGHMAN: For medical applications, we're collaborating with people in Korea, in Hanyang University, who are working with us under a Air Force program to make yarns that can convert sugars in the body into electricity, which could be very important for powering sensors that are in with the body and ultimately, hopefully, even powering a artificial heart.
FLATOW: Amazing. I'm saying too many wows this segment. Now how practical - how close are we, and as I say before, and as you said before, these things are washable, right? They will not lose their abilities if you throw them in the laundry.
Dr. BAUGHMAN: No, they are very easily washable. For example, we put titanium dioxide, a metal oxide that can be used to make self-cleaning fibers, we put this within our yarns, within the scrolls of our yarn in order to make self-cleaning textiles.
FLATOW: And how soon do you think any of these we'll see in the stores or for our usage?
Dr. BAUGHMAN: The main issue is upscaling the quantity of produced materials. In - again, and always the issue is how much money is put behind commercializing a technology. I believe that certainly within less than five years, you'll see commercial applications of this technology, perhaps even sooner. But again, it's - there are no major barriers.
We make our special yarns containing powders by simply taking these webs, these sheets of carbon nanotubes, and painting on top of them the powders and then twisting the nanotube sheet with over-lied guest into a yarn. It's very simple. The fundamental technology, the twist aspect, has been practiced since prehistoric times.
FLATOW: Wow, it sounds very - well, we're going to watch what happens...
Dr. BAUGHMAN: Thank you very much.
FLATOW: ...and pay attention to Dr. Baughman, what's going on there. Very interesting stuff. Thanks for taking time to be with us.
Dr. BAUGHMAN: It's my great pleasure to talk to you.
FLATOW: You're welcome. Ray Baughman is director of the NanoTech Institute at the University of Texas at Dallas and professor of chemistry there. Interesting stuff with nanotechnology.
Stay with us. After the break, something really interesting and useful you can do at home. Maybe you can't make the yarns, but you can do citizen science projects from gazing at galaxies, solving 3-D puzzles, sticking a ruler in the snow and then tweeting your results. You can be a citizen scientist. We'll tell you how after the break. So stay with us.
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FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY from NPR.
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