Discovery paves way for new high-powered organic batteries

WASHINGTON - Scientists may soon be able to develop new organic batteries-lightweight energy storage devices that work without the need for toxic heavy metals, courtesy the discovery of a novel way to pass electrons back and forth between two molecules.

University of Texas at Austin chemists Christopher Bielawski and Jonathan Sessler led the research, which is also a necessary step toward creating artificial photosynthesis, where fuel could be generated directly from the sun, much as plants do.

In their research, the chemists created two molecules that could meet and exchange electrons but not unite to form a new compound.

“These molecules were effectively spring-loaded to push apart after interacting with each other. After electron transfer occurs, two positively charged molecules are formed which are repelled by each other, much like magnets held in a certain way will repel each other. We also installed a chemical switch that allowed the electron transfer process to proceed in the opposite direction,” said Bielawski, professor of chemistry.

“This is the first time that the forward and backward switching of electron flow has been accomplished via a switching process at the molecular scale,” added Sessler.

Bielawski says this system gives important clues for making an efficient organic battery. He says understanding the electron transfer processes in these molecules provides a way to design organic materials for storing electrical energy that could then be retrieved for later use.

“I would love it if my iPhone was thinner and lighter, and the battery lasted a month or even a week instead of a day,” says Bielawski. “With an organic battery, it may be possible. We are now starting to get a handle on the fundamental chemistry needed to make this dream a commercial reality.”

The next step, he says, is to demonstrate these processes can occur in a condensed phase, like in a film, rather than in solution.

The molecular switch could also be a step toward developing a technology that mimics plants’ ability to harvest light and convert it to energy. With such a technology, fuel could be produced directly from the sun, rather than through a plant mediator, such as corn.

“I am excited about the prospect of coupling this kind of electron transfer molecular switch with light harvesting to go after what might be an improved artificial photosynthetic device,” said Sessler.

“Realizing this dream would represent a big step forward for science,” he concludes.

The research is published in journal Science. (ANI)