Polymer coating used to create ‘self-healing’ battery electrode

In a breakthrough which could significantly extend the lifetime of Li-ion batteries, researchers in the US have created a battery electrode that can 'heal itself'.

The advance is all thanks to a stretchy polymer developed by a team led by Professor Zhenan Bao at Stanford University. The researchers began by adding tiny nanoparticles of carbon to the polymer so that it would conduct electricity. They then used it to coat the electrode, and found that it could spontaneously heal tiny cracks that develop during battery operation. "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 Prof Bao. The resulting material breaks easily, but the broken ends are chemically drawn to each other and quickly link up again, mimicking the process that allows biological molecules such as DNA to assemble, rearrange and break down. The researchers think this approach could work for other electrode materials as well, and are now planning to refine the technique to improve the silicon electrode's performance and longevity.