Acid test for plastic battery shows potential

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Northwestern University Monica Olvera de la Cruz

Researchers have developed a technology that could see plastics replace lithium in battery design. The findings open the door on an array of power applications that could be both lighter and safer than conventional technologies.

“There is a huge effort to go beyond lithium in a flammable solvent,” said Monica Olvera de la Cruz, professor of materials science at Northwestern University’s McCormick School of Engineering in Evanston, Ill. “People have been looking at alternatives that are not explosive, like plastics. But they didn’t know how to compute what happens when you put in a charge.”

Her team looked at block copolymers (BCPs) — leading materials for use as ion conductors because they self-assemble into nanostructures that both enable ion charge transport and maintain structural integrity. BCPs innately have nano-channels through which the ion can travel, but the charges themselves manipulate the shape of the channels.

To use the material in batteries, researchers had to find a way to control the shape of the nano-channels, so that the charge moves well. Olvera de la Cruz’s work discovered that by adding salts it was possible to design a “highway system” through which the ions are transported, maximizing the power of the battery.

“If you can optimize the ability of the charge to move through the system, then you can optimize the power that actually comes out of the battery,” added Charles Sing, a postdoctoral fellow in Olvera de la Cruz’s lab.