Researchers at the University of San Diego have discovered that carbon nanotubes don’t have to be perfect to do a better job. The team of UCSD Professor Prabhakar Bandaru and grad student Mark Hoefer found that defective carbon nanotubes actually store energy more effectively than their unflawed counterparts.
The effect, which was originally studied at UCSD by grad student Jeff Nichols, rests in the creation of just the right amount of defects – enough to create additional charge sites on the nanotube, but not enough to break down its electrical conductivity. Though it’s a long way from commercialization, the breakthrough brings us one step closer to the Holy Grail of the electric car, and the entire battery-operated sustainable infrastructure of the future: a genuine quick-charging, long-lasting battery.
Carbon nanotubes are microscopic cylinders up to 100 nanometers in diameter. Their perfect atomic structure endows them with superior chemical and electrical properties, but defects do occur. The researchers first discovered that defective nanotubes used in electrodes stored a charge more effectively. By exposing the nanotubes to argon or hydrogen, they found that they could control the defects and thereby raise or lower the associated charge. Given the great strength and durability of carbon nanotubes, a nanotube-based electrode could resolve the cost, reliability, and underperformance issues of existing capacitors.
UCSD’s research joins a flood of new developments in the field of carbon nanotube batteries, including the discovery of “nanoflower” configurations that improve storage capacity, and the use of carbon nanotube/metal oxide arrays that boost the efficiency of lithium-ion batteries. As for cost, researchers at Rice University are cooking up a nanotube stew that could improve the prospects for a low cost, bulk manufacture of carbon nanotubes.