Scientists at Brookhaven National Laboratory and Stony Brook University say they have unraveled a key mystery behind an experimental technology designed to improve batteries for products ranging from automobiles to medical implants.
The scientists, who published their findings Thursday in the journal Science, say they have discovered how to better manipulate silver ions to form microscopic highway systems inside lithium batteries, speeding the flow of electricity.
"This battery actually gets better as you use it," said Amy Marschilok, a Stony Brook University professor who is part of the team working on the project.
Marschilok came to Stony Brook in 2012, along with one of the world's leading battery experts, Esther Takeuchi. They were recruited by local officials as part of an effort to leverage resources at Stony Brook and Brookhaven, and make Long Island a center for battery research.
The key to their latest project, funded by the U.S. Department of Energy, is timing and silver.
By adding silver ions to an otherwise lackluster battery, the scientists trigger a chemical reaction. As the battery begins releasing energy, those ions rearrange themselves, forming an infinitesimal grid.
Silver is among the most conductive elements. And that tiny grid acts as a highway system to speed current through the battery.
The team at Brookhaven and Stony Brook has been working with the technology since 2009. But until now, it wasn't clear to them how the silver ions behaved inside the battery. To find out, they used a massive X-ray machine at Brookhaven.
That machine, the National Synchrotron Light Source, allowed them to see inside the battery. It turned out that if scientists slowed the rate at which the battery initially generated energy, the silver ions formed a stronger and more complete highway system.
That made the battery more powerful and efficient. So by starting the battery slowly, it ultimately became faster.
"By changing the rate at which we discharged the battery," Marschilok said, "it actually affected the chemistry happening inside the battery."