Concrete may have found it's killer app in graphene. But there are plenty of different materials that could find a place in our infrastructure, he says. To figure out how graphene might change manufacturing in the future, we spoke with the director of Harvard's Graphene Research Center, who explained that graphene, the strongest material known to man, could potentially be used in everything from cell phone batteries to roadways. The Science of Graphene We often hear about carbon nanotubes, a related substance, as a potential material that might make our airplanes and cell phones thinner. But what makes graphene different from other carbon nanotubes? When scientists want to start a new material that is exceptionally strong, lightweight and good at conducting heat and electricity, the first thing they do is look for something to replicate, says Walter Leeb, director of the Graphene Research Center and a chemistry professor at Harvard. "That's the essence of graphene," he says. But unlike carbon nanotubes, graphene is a flat, two-dimensional crystal. It can be easily shaped into sheets, and scientists are experimenting with its properties. While carbon nanotubes are naturally occurring, they are "extremely expensive," Leeb says. "When you can make a sheet of pure graphite you can use the material that's around us." But while it is extremely strong, graphene has a weak spot. "It's as strong as aluminum, but it has no strength in the plane," he says. That said, graphene is flexible, meaning it could be used in construction. "In the future there will be a lot of graphene going on," Leeb says. "Anywhere where you want to be lightweight and strong." When we think of building the future of any material, carbon nanotubes are going to be important because "there's no better material than carbon to be light, because carbon is the strongest," he says. But graphene is better because of its extreme flexibility, allowing for weight loss in the future and potentially allowing us to build thinner materials, he says. But it is not only carbon nanotubes that are important; carbon itself is a super important component of just about any technology we think of. "When you think of carbon and how much you use it in the everyday, you would like to be using carbon in every single product. So I would say that we're moving more towards new carbon structures in our future." But how will graphene be applied in the future? How will we use it in manufacturing? Graphene-based computers are on the market now. And "it's the computer of the future," Leeb says. There is no doubt that graphene will be used in manufacturing, he says. "Theoretically, we can make carbon from a gas and put it on anything," he says. And so theoretically, you can make any material out of graphene. Because of its electrical properties, "you can start building circuits that never existed before," Leeb says. "It is easy to use electricity at the nanoscale." It has the largest thermal conductivity in any material, and it's great at conducting electricity. "And a lot of heat will be dissipated in a tiny space." It is so good at conducting electricity that it can make other materials thinner. "You can make it into thinner, smaller, more versatile, better components," Leeb says. When it comes to manufacturing, it will become a matter of finding a way to create a device that can be scaled up, he says. "You can have a microfab plant that can run for a few years. You can run a few millions of feet of carbon for a few hundred dollars," he says. Graphene will be combined with semiconductors and thin films. But Leeb says it is too expensive to use right now. "It takes a lot of money to make it and it's not good enough yet to use." It has been a hard slog for his lab to try to create such a simple product because it is expensive to produce and has to be combined with something else to make it conductive. "But I think we're close." And when it comes to the environment, Leeb doesn't see graphene as a big issue because it is so cheap. "It is so expensive to go make it on a clean room scale that it's basically a waste," he says. Graphene isn't strong enough to be used to build materials like a bridge, but it has been used in the wings of some drones. "It's strong and you can roll it around, but it's very thin so the load would be different." You need to keep the material thin so that it would actually be stronger than another material. But that's the kind of thing that may be happening in industry now, he says. "Industries are trying to figure out where they want to make their profits." For many industries, the cost of graphene is not a big issue right now because carbon is so cheap and abundant, he says. "So they say, 'Let's find out what graphene is good for and use it as a building block,'" he says. "They are looking to do something new with graphene, but the thing that makes it unique is when you use this material, you need to make something out of it." Another reason graphene may not be practical for other products is the size and scale of them. It is a lot smaller than we think of it because "we're used to seeing the material when we hear about graphene," Leeb says. It is still in the experimental stage in its own right, he says. "And graphene is used everywhere in laboratories, on a small scale," Leeb says. Graphene's Future in Architecture Carbon nanotubes are being used right now to make some strong, lightweight materials, and graphene looks like it is going to do that much better, Leeb says. A strong, lightweight material could be put into a structure that has to be light, Leeb says. "If you have a large building and the steel frames that go into it are heavy, you want something that's light." Graphene is light and strong, he says. Right now, graphene hasn't been used in architecture because it's expensive. "It's not practical to use right now," he says. But "there is a strong push in architecture for light-weight materials," Leeb says. "The idea of lighter and stronger and cheaper is very attractive for the construction industry." Right now, there isn't anything that uses graphene in this way, he says. "But I think we will see graphene in architecture at some point." Graphene is also being used in electronics, in making computer chips. "You can make all these electronic gadgets that will last longer, be lighter, and more robust." At first, graphene wasn't a good option for electronics because it was too expensive and not practical, Leeb says. "But now because graphene has gotten so cheap, it has become very attractive to use." While it is stronger and lighter, graphene might not be able to replace silicon for a long time, he says. But there is something exciting happening in industry and that could potentially change what he thinks in the future, he says. In "some cases, we might be able to replace silicon with graphene in about 15 to 20 years, but you have to wait a long time for it to happen," Leeb says. Graphene could be a superior option for electronics because its electrical conductivity is better. "It is more efficient, so it would power more devices," he says. That could allow for lighter batteries. And graphene could make cell phones and computers lighter. "People are working on a computer that would be as big as your palm," Leeb says. In addition to electronics, graphene could change the design of airplanes. "With stronger, lighter components you can decrease the weight of the airplane," Leeb says. And graphene can be used in the batteries of electrical devices. "You can make batteries that last longer and produce the same amount of power that a lithium battery does today," Leeb says. While people are more excited about the future of the cellphone, he says the future is in the cars. "If you can decrease weight in a car and it can go faster, you're reducing your energy consumption," he says. "I think this technology can revolutionize transportation." But while technology is advancing at a faster rate than the cost of production, that will eventually change, he says. "This is still a long-term project that's going to get cheaper, better, and faster." So while graphene is strong and light, it could be used in other materials and that will likely change our material needs in the future, he says. "That's what excites me about the technology. It is not just one application, but the fact that we have such a