Date: 01/08/2011

Nano-sized batteries to power mobiles: Rice researchers build battery in a nanowire

The team led by Indian origin scientist Prof. Pulikel Ajayan of Rice University Labs has packaged lithium ion batteries into a single nanowire and the researchers believe that this could soon be a rechargeable power source for new generations of nanoelectronics; as reported by the American Chemical Society journal Nano Letters.

Two versions of batteries have been tested in the research. The first was a sandwich with nickel or tin anode, polyethylene oxide (PEO) electrolyte and poly aniline cathode layers; it was built as proof that lithium ions would move efficiently through anode to electrolyte and then to super capacitor-like cathode that gives the device ability to charge and discharge quickly.

The second bunch was with same capabilities into a single nanowire. The researchers built centimeter-scale arrays containing thousands of nanowire devices with each 150 nanometers wide. A nanometer is a billionth of a meter, thousands of times smaller than a human hair.

"The idea here is to fabricate nanowire energy storage devices with ultrathin separation between the electrodes; this affects the electrochemical behavior of the device. Our devices could be a very useful tool to probe nanoscale phenomenon", states the release.
The experimental batteries are about 50 microns tall. The nanowire devices show good capacity; the researchers are in the process of fine-tuning the materials to increase its ability to repeatedly charge and discharge, which now drops off after a about 20 cycles.

Prof. Ajayan's team has been inching toward single-nanowire devices for years. He did his B. Tech in metallurgical engineering from Banaras Hindu University in 1985 and Ph.D. from Northwestern University US in 1989.