Spark of Hope for Electric Cars : Science: A new mix of battery components shows promise in the search for practical, non-polluting vehicles.

Arizona State University researchers have developed a rubbery conducting substance that may make it possible to combine the superior energy storage of lithium batteries with the convenience of dry cells, a potentially important step toward mass-producing practical electric cars.

Key to the concept, which scientists said still may be years from the marketplace, is a reversal of the ratio of the two main ingredients most often used in experimental electrolyte, the chemical substance that conducts electricity inside the battery.

Rather than lightly “salting” some plastics to make a solid electrolyte that conducts poorly, chemistry professor Charles Austen Angell and his colleagues say in today’s issue of the journal Nature that they tried adding a little plastic to a vat of molten lithium or aluminum salts.

The resulting rubbery electrolyte stores energy well and releases it quickly, they report.

Private and government scientists are aggressively studying these so-called lithium-polymer cells because of their potential to hold more energy in less space than conventional lead-acid batteries. Better batteries can make electric cars weigh less, accelerate faster and go longer between recharges, thus making them more competitive with gasoline-powered cars.

“Batteries are the thing that give you the range and cost the most, so you want them to be as light, compact and powerful as possible,” said Richard Schweinberg of Southern California Edison. The utility is part of the Advanced Battery Consortium, which is spending $53 million on battery research. Most is focused on lithium-polymer technology.

Electric car technology is vital to California because the state has ordered that 2% of new cars sold here in 1998 be pollution-free. By 2003, that is scheduled to rise to 10%, or 200,000 vehicles. Electric cars are the only vehicles known to satisfy the requirement.

In light of this, news of the new battery design drew praise--and skepticism.

“A way has been opened to a new generation of lithium batteries,” said Malcolm Ingram of the University of Aberdeen in Scotland.

But some scientists in the United States criticized the electrolyte recipe cited by Angell and his colleagues as impractical. The article discusses electrolytes with lithium chlorate or aluminum chloride, salts that readily absorb moisture from the atmosphere. This is a problem because the water they absorb can corrode other vital battery components.

“Turning it all around--making a polymer-in-salt instead of a salt-in-polymer--is a good idea, a clever approach,” said one scientist, a competitor in lithium-polymer research who agreed to speak only if not named. “But this particular combination (of salts) isn’t going to do it.”

Angell, in a telephone interview, said that he and his colleagues, Changle Liu and Edwardo Sanchez, concede that “the salts we used in our demonstration are probably not acceptable in commercial applications.”

“But,” he added, “there are a lot of other candidates that we hadn’t tried (at the time the article was submitted to the journal last August) because they were difficult to handle or difficult to obtain.”

He said a number of new electrolyte recipes have been tried, some of which work better than those cited in Nature. He declined to be specific because his research is proprietary.

Ingram agreed that the new approach was more important than problems with the specific recipe.

“These are questions which one expects can be dealt with in time,” he said.