Link: http://www.nature.co...5/030825-8.html
Date: 09-01-03
Author: JOANNE BAKER
Title: Microbatteries patented
Comment: Put this together with the nanomotor
and we've got an atomic submarine... kinda..
Microbatteries patented
US researchers have patented a technique to manufacture batteries a thousandth of a millimetre across.
Building a microscopic power unit is a first step towards propelling machines that operate at the atomic scale. Miniature robots might one day sniff out chemicals in the environment or deliver drugs inside the body.
The new 'microbattery' works like a car battery, but is around one-millionth the size. To make one, the device's creators - a team at the University of Tulsa, Oklahoma - pour molten plastic into the holes of an aluminium oxide honeycomb so fine that 60 pores straddle the width of a human hair1.
Electrically charged ions pass through this plastic, called the electrolyte, between positive and negative electrodes that seal the ends of the pores.
The prototype produces only a tiny electrical current - about a millionth of a milli-amp. "You're not going to power a flashlight with it," admits team leader Dale Teeters. But he hopes that it might be enough to drive microscopic machines of the future.
The microbatteries are too small to charge with conventional wires, so the team uses a machine called an atomic-force microscope to touch individual atoms on the electrodes and connect the electrical circuit.
For this reason, some researchers feel that it is premature to describe the set-up as a battery. "A battery is a whole structure - you need electrical wires to use it," argues Mino Green of Imperial College, London, who develops small batteries to power silicon computer chips. "Nature is full of [such] electrochemical cells," he points out.
"To be practical, some means of charging them, removing them from the template and connecting them to wires must be developed," agrees Charles Martin of the University of Florida in Gainesville, who is also designing tiny batteries. Nonetheless, "it's a great lab experiment", he enthuses
