Introducing The Paper Battery

It might sound a little like science fiction, but really it’s science fact. Researchers at Rensselaer Polytechnic Institute (RPI) have created a batterythat’s 90 percent cellulose; in other words, it’s made of the same plant cells used in nearly every type of paper.   The battery can be twisted, rolled, even folded and cut withoutany loss of efficiency or integrity. The paper batteries can even be stacked, like a ream of paper, to increase the output. What powers it are aligned carbon nanotubes in the paper, which act aselectrodes and allow the battery to conduct electricity.   The battery is described in a new paper, “Flexible Energy Storage Devices Based on Nanocomposite Paper,” which waspublished this week in the Proceedings of the National Academy of Sciences.   According to Robert Linhardt, professor of biocatalysis and metabolic engineeringat RPI, the idea came from a collaboration between three different groups of students. They developed three separate devices that can be used individually or together: There’s the battery, apiece of paper a few inches across that is black on one side and gray on the other; there’s also a supercapacitor, and finally a hybrid device, which combines the two. The devices can beprinted like paper.   “If we stack 500 sheets together in a ream, that’s 500 times the voltage,” explained Professor Linhardt. “If we rip the paper in half we cut power by 50%.So we can control the power and voltage issue.” Its size makes the battery ideal for portable devices, but it could easily work in a pacemaker, although bigger things, like cars, remainproblematic. But it’s all still some way from the market. The supercapacitor will likely be the first to roll out commercially, and even that will take a few years.