The battery of the future

Wed, January 24, 2007

By GILES CREVIER


Dream of recharging your mobile phone or car battery in seconds? This may soon be a reality. Scientists at the Massachusetts Institute of Technology (MIT), have built a supercondenser made of nanotubes. And it spells the end of the traditional electric battery.

THE CONDENSER

Used in all radios, this was the first device invented by man to accumulate electrical energy. The condenser was invented simultaneously in 1745 by German and Dutch scientists. In 1782, the true inventor of the electric battery, the Italian Alessandro Volta, coined the term "condenser". A condenser does much the same as a battery, but they work much better when used together.

THE PRINCIPLE

When activated by electricity, two metal plates separated by a non-conductive element trap ions (which are charged particles) into a substance called electrolyte. The plates each attract ions of opposite charges (positive or negative). Contrary to a traditional battery, which works with chemical elements, the condenser works essentially as a physical principle. In this case, the charge is increased by increasing the space between the plates (electrodes) and getting them close again. A condenser becomes a supercondenser when the space between the electrodes increases by a factor of a trillion. Thus a supercondenser can recharge in seconds and provide a strong discharge, also in seconds.

NANOTUBES

Scientists at MIT have come up with carbon nanotubes, which will provide more energy than today's best batteries, powered by lithium-ion exchange. Several nanotubes are grown to a length of 2.5 meters, each separated from its neighbour by a mere 5 to 10 nanometers. With a 20 to 30 fold increase in surface area, the ions can recharge much faster with an electrical output comparable to a lithium-ion battery. MIT scientists hope to build the first prototype of this new battery within six months.

The negative pole: Tension between the two condenser poles charge the electrolyte to the opposing pole (positive or negative).

Electrolyte: a liquid capable of conducting electricity.

A porous membrane: it allows ions to pass through.

Nanotube: very small carbon molecules that can conduct electricity which can then be assembled to form pipes.

A nanotube is about as big as the finest of human hair.

The ions stick to the sides of these pipes.

USES

The new batteries will be used in medical devices, in cars, mobile phones, iPods, etc. Though its charge won't last any longer than in the lithium-ion battery, the battery's life will be longer and it will recharge almost instantly.

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GREAT BALLS OF FIRE

The mystery of luminous, grape-fruit size spheres reported during lightning storms may have been solved by researchers in Brazil. Thousands of people have reported seeing the strange, glowing orbs. One eyewitness in Oregon saw a glowing ball burn through the screen door of a house and navigate down to the basement. In another report, ball lightning bounced on a Russian teacher's head more than 20 times before vanishing. The theory is the glowing balls form when lightning strikes any silica present in soil, turning it into vapour. As the vapour cools, the silicon condenses into a floating aerosol bound into a ball by charges that gather on its surface and it glows with the heat of silicon recombining with oxygen. To test the idea, Brazilian researchers took wafers of silicon, placed them between two electrodes and zapped them with currents of up to 140 amps, creating an electrical arc that vaporized the silicon. The arc spat out glowing fragments of silicon but also - sometimes - orbs the size of ping-pong balls.

PLANT LIFE IS HELL

In the war between plants and insects, scientists have discovered wheat has a way to destroy enemies. U.S. researchers discovered a wheat gene that produces proteins that attack the stomach lining of the crop-destroying Hessian fly larvae so the bugs starve to death. The Hessian fly causes catastrophic loss if not controlled by resistant plants.

ABOUT 90 YEARS TO LATE

Here's why the 1918 influenza virus that swept the world was so deadly. Using monkeys infected with the virus, an international team at the National Microbiology Laboratory in Winnipeg discovered the virus triggers the body's immune system to unleash an attack on the lungs. As the immune cells attack the respiratory system, the lungs fill with fluid and victims, in essence, drown. The research, published in the journal Nature, suggests it may be possible in future outbreaks to stem the tide of death.

UPTOWN BIRDS

Urban sprawl might not be as harmful to wildlife as previously thought, according to a new study by U.S. researchers. Using field surveys and digital maps of habitat, researchers compared the diversity of bird populations in natural forests, tree plantations and urban sprawl areas along the Cumberland Plateau in Tennessee. They found tree plantations had substantially less bird population diversity than did native forests and urban sprawl areas - which had more diversity than even native forests.