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Purdue engineers have figured out a way to tackle plastic landfills while also improving batteries – by putting ink-free plastic soaked in sulfur-containing solvent into a microwave, and then into batteries as a carbon scaffold.

Lithium-sulfur batteries have been hailed as the next generation of batteries to replace the current  variety. Lithium-sulfur batteries are cheaper and more energy-dense than  ions, which would be important characteristics in everything from electric vehicles to laptops.

But the knock on  to this point is that they don't last as long, being usable for about 100 charging cycles.

Purdue researchers have found a way to increase the life span in a process that has the added bonus of being a convenient way to recycle . Their process, which was recently published in ACS Applied Materials and Interfaces, shows that putting sulfur-soaked plastic in a microwave, including transparent plastic bags, transforms the material into the ideal substance for increasing the life span of the forthcoming batteries to more than 200 charging-discharging cycles.

"No matter how many times you recycle plastic, that plastic stays on the earth," said Vilas Pol, associate professor in Purdue's School of Chemical Engineering. "We've been thinking of ways to get rid of it for a long time, and this is a way to at least add value."

The need to reduce landfills runs parallel to making lithium-sulfur batteries good enough for commercial use.

"Because lithium-sulfur batteries are getting more popular, we want to get a longer life sucked out of them," Pol said.

Low-density polyethylene plastic, which is used for packaging and comprises a big portion of plastic waste, helps address a long-standing issue with lithium-sulfur batteries – a phenomenon called the polysulfide shuttling effect that limits how long a battery can last between charges.

Researchers have discovered that soaking low density plastic in a sulfur-containing solvent, putting it into a microwave and transforming it into a carbon scaffold makes lithium-sulfur batteries last longer and retain elevated capacity. Credit: Purdue University image/Patrick Kim

Lithium-sulfur batteries, as their name suggests, have a lithium and a sulfur. When a current is applied, lithium ions migrate to the sulfur and a chemical reaction takes place to produce . The byproduct of this reaction, polysulfide, tend to cross back over to the lithium side and prevent the migration of lithium ions to sulfur. This decreases the charge capacity of a battery as well as .

Check out their research in action here!

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