American scientists use self-healing technology to build more long-lived lithium-ion batteries

University of Illinois(University of Illinois); UI) researchers have found that a method that can apply self-healing technology to lithium ion batteries is expected to create reliable and more long-lasting batteries.

Researchers have developed a new type of battery that uses Silicon nanoparticle composites on the negative side of the battery and binds the composites in a novel way -- a problem inherent in Silicon cells.

Nancy Sottos, a professor of materials science and engineering at the University of Illinois, and Scott White, a professor ofspecial engineering, led the research team and published the study in the Journal of Advanced Energy Materials.

Nancy Sottos, a professor of materials science and engineering at the University of Illinois, and Scott White, a professor ofspecial engineering, led the research team to develop Silicon nanoparticles that can be used for battery anodes and are expected to be used to create more reliable and long-acting batteries.

"For self-healing materials, this research is quite new because it can be applied to materials that store energy," White said. "This is a completely different type of target. In addition to restoring structural performance, it also has the ability to heal energy storage. "

Inside lithium-ion batteries used to power portable devices or electric vehicles, negatively charged electrodes or anodes are usually made of graphite particle composites. These batteries work well, but they take a long time to get on, and as time progresses, the charging duration becomes the same as the new battery.

"Silicon has a very high capacity, and this high capacity allows you to get more energy from the battery, but due to the battery cycle and its self-pollination, it also experiences a lot of expansion. "

Past studies have found that battery anodes made of nanometer sized Silicon particles are less likely to decompose, but there are other problems.

"The battery is continuously charged and discharged, through one, two, three times to the final capacity loss, because the Silicon particles begin to break away from the binder," White said. "

In order to solve this problem, the research team further improved the Silicon anode by giving it the ability to repair itself. This self-healing phenomenon occurs through the reversible chemical bond between Silicon nanoparticles and polymer adhesives.

"This dynamic rebonding process essentially holds Silicon particles together with polymer adhesives, significantly improving the long-term performance of the electrode," Sottos said.

The researchers tested new batteries that did not use reversible chemical bonds and found that they could maintain 80 % of their initial capacity even after 400 charge cycles.

These batteries also have a higher energy density, which means they store more electricity than graphite-anode batteries of the same size.

"The higher the energy density, the better. Another option is to add more batteries, but this adds a lot of weight, especially as electric cars are facing such problems, "Sottos said.

Future research will include looking at how this self-healing technique works with solid-state batteries, the researchers said. Scientists are being urged to look in this direction in recent accidents where lithium-ion battery liquids have spontaneously ignited or even exploded.

The research project is sponsored by the Center for Electrochemical Energy Science, an advanced energy research center funded by the US Department of Energy's Office of Science and Basic Energy Science.

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