Self-Healing Battery Electrode Opens Path to Next Generation Electronics

Ever hear of a battery that can heal itself? Well you're about to. Scientists have created the first battery electrode that can heal itself, opening a new path for making the next generation of lithium ion batteries for electric cars, cell phones and other devices.

"Self-healing is very important for the survival and long lifetimes of animals and plants," said Chao Wang, one of the researchers, in a news release. "We want to incorporate this feature into lithium ion batteries so they will have a long lifetime as well."

The self-healing battery electrode works due to a stretchy polymer that coats the electrode. This polymer binds it together and spontaneously heals tiny cracks that develop during battery operation. The polymer itself has tiny nanoparticles of carbon within it so that it conducts electricity.

"We found that silicon electrodes lasted 10 times longer when coated with the self-healing polymer, which repaired any cracks within just a few hours," said Zhenan Bao, one of the researchers, in a news release.

In fact, the battery's capacity for storing energy is in the practical range now. In addition, the electrodes themselves worked for about 100 charge-discharge cycles without significantly losing their energy storage capacity. Although that's still quite a way from the 500 cycles for cell phones and 3,000 cycles for an electric vehicle, it's still a step in the right direction.

So how exactly is this self-healing coating made? The scientists deliberately weakened some of the chemical bonds within polymers, which are long, chain-like molecules with many identical units. The resulting material broke easily, but the broken ends were chemically drawn to each other and quickly linked up again. This mimicked the process that allowed biological molecules, such as DNA, to assemble, rearrange and break down.

The researchers are still investigating ways to store more energy. Yet they believe this approach could work for other electrode materials, as well. They plan to continue to refine the technique to improve the silicon electrode's performance and longevity. In the future, we could see this technology in cell phones, electric cars and other electronics.

The findings are published in the journal Nature Chemistry.