Date:1st Aug 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
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.