Battery Life

Batteries aren’t just for inanimate objects anymore.

From smartphones to toys to cars, these energy storage devices power many of the things we rely on every day. But they haven’t been able to directly power us because batteries generate the wrong kind of electrical current—ZAP!

Until now, that is. University of Maryland engineering researchers have found a way to invert how a battery works. Instead of ions flowing between electrodes inside a battery while electrons carry electricity out of the battery, their revolutionary concept corrals the electrons, instead sending an ionic current out through blades of Kentucky bluegrass.

Ionic current is the form of electricity present in all earthly life, making the battery produced by a team led by Liangbing Hu, an associate professor of materials science and engineering, the first to interface with animal and plant cells. 

It’s so new that no applications have yet been tested, but Hu is thinking big—including the possibility of directly interfacing with the nervous system to overcome disease and injury leading to paralysis and motor problems.

“The potential applications of this reverse battery may include the development of the new devices to manipulate neuron activities and interactions,” Hu says.

The technology could also deliver ionic drug treatments for ailments ranging from cancer to psychological issues, he says. For instance, lithium is often used to treat bipolar disorder, but side effects may result from the drug suffusing the body. The new battery technology could potentially send a lithium ion current only to the area of the brain that needs it.

And on the far horizon, the technology might help turn concepts that seem like cybernetic science fiction into reality: “In an even bigger picture, we can also establish the potential (for) direct communication between human and machines.”

The experiment itself was both simple and highly novel in concept, says Chengwei Wang, a postdoctoral researcher and lead author of a paper about the invention published in Nature Communications.

Wang put blades of bluegrass in a lithium salt solution—the vascular structure of the grass is ideal for soaking up the electrolyte—and attached them to a pair of electrode tubes connected by a metal wire. Electrons ping-ponged through the wire between the tubes, while ions flowed out through the grass and electrical contacts at the end of the tube into a petri dish where the current energized phosphorescent living cells in a petri dish.

“It’s actually quite straightforward, and anyone who understands batteries can look at it and say, ‘Oh yes, I get it,’” Wang says. “What’s new is the idea of the inversion creating ionic current to use in this way. Now we need the biomedical people to take it and develop the applications.”