|August 14, 1999, 11:00 AM||#1|
Join Date: March 1, 1999
This story may provide a fix for you flashlight junkies out there.
AUGUST 12, 21:07 EDT
Scientists Create `Super Batteries´
By LAURAN NEERGAARD
Associated Press Writer
WASHINGTON (AP) — A new generation of batteries that could run that pink bunny ragged may be on the horizon: They last 50 percent longer than today's batteries, thanks to a ``super-iron´´ component that promises to be easy and affordable to manufacture. They´re still under development, so don´t look for them in local stores soon.
But researchers at the Israel Institute of Technology invented super batteries that could run CD players and flashlights — and say the new batteries also could come in the rechargeable forms needed to power camcorders, laptop computers, even electric cars. ``Improved batteries are needed,´´ says Stuart Licht, a chemistry professor who led the research team in trying a host of materials, from sulfur to tin, before they discovered an unusual form of iron boosts battery life.
``From the outside, the super-iron batteries look identical to conventional´´ AA or AAA batteries, he said in an e-mail interview from Haifa. ``The difference is within, and in the much greater energy generated by the super-iron battery.´´
The new batteries have 50 percent more energy than traditional batteries, Licht reports in Friday's edition of the journal Science. When he tested gadgets that drain batteries at extra-high rates, such as portable CD players, he found that the super iron also has extra conductivity, leading to another advantage. ``A conventional AAA-size alkaline battery may last only a few minutes at high-drain rate, but under the same conditions, a AAA super-iron battery discharges for well over an hour,´´ he said. Battery experts called the discovery promising. ``It´s a significant advance scientifically,´´ said Jack Winnick, a chemical engineer at the Georgia Institute of Technology. ``I think the manufacturers will be intrigued by it. The market right now for these alkaline cells is so enormous ... that if they could make a rapid replacement, I think they would.´´
But Licht declined comment when asked if manufacturers already are interested in commercializing his invention. Some 60 billion alkaline batteries — the type most sold — are used worldwide each year. But their basic internal design hasn't changed much since the late 19th century: They typically contain a zinc anode and a manganese dioxide cathode.
Batteries convert chemical energy into electrical energy through reactions at the anode and cathode. When active materials at either electrode are used up, the battery dies. In most alkaline batteries, the cathode dries up long before the anode.
So the scientists made a new cathode from ``super iron,´´ a chemically unusual form called iron(VI) that scientists long believed too unstable for batteries — because if it came into contact with liquids, it disintegrated into rust in minutes. But Licht discovered that the caustic solutions commonly used inside batteries actually stabilize the super iron so it doesn´t decay. The super iron absorbs more electrons than the old-fashioned cathode, making it more powerful, Licht´s team showed. Industry — and consumers — are demanding longer-lasting batteries for a variety of uses. Electric cars, for instance, have been stalled by the quest for an affordable battery that can go longer distances without frequent recharging.
Most such research has focused on lithium-based batteries, where highly energetic but lighter-weight lithium compounds are used to make anodes, said Georgia Tech's Winnick.
But lithium is much more scarce than iron and a hundred times more expensive, Licht said.
There are still questions about the new batteries that require further testing, such as how long a shelf life they will have. Still, if the batteries ultimately are sold, disposing of used ones will cause a little less environmental damage than today's batteries because the super-iron eventually just rusts, Licht said.