Storing Power in a Sheet of Paper
It resembles a sheet of black paper, like a piece of construction paper a child would draw on. But it’s really a battery lightweight, ultrathin, completely flexible, and geared toward meeting the trickiest design and energy requirements of tomorrow’s gadgets, implantable medical equipment, and transportation vehicles.
Along with its ability to function in temperatures up to 300 degrees Fahrenheit and down to 100 below zero, the device, created by researchers at Rensselaer, is completely integrated and can be printed like paper. The device is also unique in that it can function as both a high-energy battery and a high-power supercapacitor, which are generally separate components in most electrical systems. Another key feature is the capability to use human blood or sweat to help power the battery.
How It’s Made
The semblance to paper is no accident: more than 90 percent of the device is made up of cellulose, the same plant cells used in newsprint, loose leaf, lunch bags, and nearly every other type of paper.
Rensselaer researchers infused this paper with aligned carbon nanotubes, which give the device its black color. The nanotubes act as electrodes and allow the storage devices to conduct electricity. The device, engineered to function as both a lithium-ion battery and a supercapacitor, can provide the long, steady power output comparable to a conventional battery, as well as a supercapacitor’s quick burst of high energy.
“It’s essentially a regular piece of paper, but it’s made in a very intelligent way,” said Robert Linhardt (pictured third from left above), the Ann and John H. Broadbent Senior Constellation Professor of Biocatalysis and Metabolic Engineering at Rensselaer.
“We’re not putting pieces together it’s a single, integrated device,” he said. “The components are molecularly attached to each other: the carbon nanotube print is embedded in the paper, and the electrolyte is soaked into the paper. The end result is a device that looks, feels, and weighs the same as paper.”
The creation of this unique nanocomposite paper drew from a diverse pool of disciplines, requiring expertise in materials science, energy storage, and chemistry. Along with Linhardt, researchers include Pulickel Ajayan, professor of materials science and engineering, and Omkaram Nalamasu, former Rensselaer professor of chemistry with a joint appointment in materials science and engineering. Senior research specialist Victor Pushparaj, along with postdoctoral research associates Shaijumon Manikoth, Ashavani Kumar, and Saravanababu Murugesan, were also lead researchers of the project. Others include research associate Lijie Ci and Rensselaer Nanotechnology Center Laboratory Manager Robert Vajtai.