Ordinary office paper coated with an inky layer of carbon nanotubes or nanowires can make a lightweight, flexible and highly conductive battery or superconductor, according to Stanford University researchers.
The scientists had previously experimented with making batteries using a similar process of painting nanomaterial ink onto a thin layer of plastic. But in an unexpected twist, they found that pores in paper fibers make it hold the ink better than plastic, for a more durable battery.
The research, led by nanomaterials science and engineering researcher Yi Cui, was described this week in the Proceedings of the National Academy of Sciences.
"If I want to paint my wall with a conducting energy storage device," Cui said in a release, "I can use a brush." His group found that even when the paper-based batteries were folded, crumpled or soaked in an acidic or basic solution, their performance did not degrade.
The result: a battery that is uncommonly lightweight that can be produced at a low cost because it is simple to make.
The researchers said the conductive paper could be used in lithium-ion batteries in place of metallic components, where its light weight and scalability would provide an advantage over technologies now in use.
Supercapacitors, energy storage devices that hold a charge for a short period, were made with the technique and found to work for 40,000 charge-discharge cycles, a performance far better than standard lithium-based alternatives, Cui said.
A potential application of the technology, he said, could be for large-scale energy storage on the electric grid. Such storage is important for smoothly integrating intermittent renewable energy resources like wind and solar into the electric infrastructure.
The material also charges and discharges quickly, making it potentially useful in hybrid or electric vehicles.