Scientists at Oregon State University have found a way to convert tree cellulose into high-tech energy storage devices. Because cellulose is a key component of trees and the most abundant organic polymer on earth this discovery will have a profound impact in industry. Scientists were able to heat the tree cellulose in a furnace in the presence of ammonia to create the building block for supercapacitors for use in industrial electronic applications. Supercapacitors are extraordinarily, high-power energy devices for which production has been held back by cost and difficulty in producing high-quality carbon electrodes.
The new approach just discovered at OSU can produce nitrogen-doped, nanoporous carbon membranes — the electrodes of a supercapacitor — at low cost, quickly, in an environmentally benign process. The only byproduct is methane, which could be used immediately as a fuel or for other purposes.
“The ease, speed and potential of this process is really exciting,” said Xiulei (David) Ji, an assistant professor of chemistry in the OSU College of Science, and lead author on a study announcing the discovery in Nano Letters, a journal of the American Chemical Society.
“For the first time we’ve proven that you can react cellulose with ammonia and create these N-doped nanoporous carbon membranes,” Ji said. “It’s surprising that such a basic reaction was not reported before. Not only are there industrial applications, but this opens a whole new scientific area, studying reducing gas agents for carbon activation.
“We’re going to take cheap wood and turn it into a valuable high-tech product,” he said.
These carbon membranes at the nano-scale are extraordinarily thin — a single gram of them can have a surface area of nearly 2,000 square meters. That’s part of what makes them useful in supercapacitors. And the new process used to do this is a single-step reaction that’s fast and inexpensive. It starts with something about as simple as a cellulose filter paper — conceptually similar to the disposable paper filter in a coffee maker.
The exposure to high heat and ammonia converts the cellulose to a nanoporous carbon material needed for supercapacitors, and should enable them to be produced, in mass, more cheaply than before.
A supercapacitor is a type of energy storage device, but it can be recharged much faster than a battery and has a great deal more power. They are mostly used in any type of device where rapid power storage and short, but powerful energy release is needed.
Read more at Oregon State University.
