Pasquali heads a project at Rice aimed at making carbon-nanotube fibers that are very dense and therefore very strong and conductive. These pure nanotube fibers could eventually be used as low-loss electrical transmission cables or in super-strong structural materials. “Once you have a fiber, you can weave it, put it into a polymer [such as fiberglass], or make a fabric,” says Pasquali, who notes that textile processing is relatively low-cost.
Baughman’s team made a battery-electrode fabric using lithium-iron-phosphate powders. The fabric is almost 99 percent active material, so it could be used to make lightweight batteries.
And of course, once something can be made into a fabric, it can also be worn.
Yi Cui, associate professor of materials science and engineering at Stanford University, is also developing textile-based energy-storage devices. He believes that wearable power supplies could one day power everyday gadgets. The important qualities are cost, weight, and the ability to charge and discharge rapidly, and textile electrodes seem to be ideal in these respects. But they are unlikely to scale well for applications that require a high total energy-storage capacity, like batteries for electric cars.
The University of Texas researchers plan to take the project in several directions. In addition to testing different powders, they are experimenting with different ways of depositing them.
Someday, the yarns could be used to produce large quantities of material for structural manufacturing. “Right now it’s more sensible to talk about batteries, not airplane wings, because of the tonnage [of materials] required,” says Baughman. His group is working with a few companies to further develop the yarns, including chemical manufacturer Lintech and carbon-nanotube textile maker Nanocomp.