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Alberta researchers use eggshells to build better battery

Your morning omelette may hold the solution to your quick-dying smartphone battery.

University of Alberta researchers David Mitlin and post-doctoral fellow Zhi Li have developed a fast-charging supercapacitor using eggshell membranes — a plentiful egg industry byproduct.

“We sell the liquid egg whites and the yoke to food processors, and we have no use for the eggshells,” said Li. “But we have the technology to separate the eggshell membranes from the physical hard shell.”

The membranes have a unique structure that allows them to hold three times the electrical charge of a battery, making them ideal for use as a supercapacitor.

“It’s similar to a battery because it stores energy, but it’s different from a battery because it can charge very quickly,” said Li. “You can charge it in 30 seconds or, in some cases, even five seconds. That’s impossible for a battery.”

And like a battery, these egg-powered supercapacitors can be used in electronics, vehicles, and yes, even smartphones.

“If you have an iPhone, your battery is dying in one year or two years, but if you have a supercapacitor, it will probably last you more than 10 years,” he said. “That’s amazing for some applications.”

If it all works out, it’ll be great news for egg farmers, too, said Jenna Griffin, industry development officer for the Egg Farmers of Alberta.

“The market for shell eggs has been declining over the years,” she said. “There’s been a trend toward more processed and liquid egg products.”

While there are some low-value markets for eggshells, many processors simply send them to the landfill. But making batteries could use a fair number of them.

“If you do some back-of-the-envelope numbers, you can see the practicality of what they’re doing,” said Griffin. “There’s somewhere between 150 million to 200 million dozen eggs broken in Canada, and from that byproduct, they can make about seven million batteries.”

Every year, supercapacitor production in the world nearly doubles to meet the growing demand for better power sources. But this is the first supercapacitor built using eggshell membranes, said Li.

“There is a market for supercapacitors, and there are supercapacitors available,” said Li. “But there is no commercial capacitor available utilizing this kind of functionality.”

While Mitlin and Li have not yet commercialized their findings, they said they hope to scale up production as funding becomes available. Until then, Li will continue exploring the energy potential of other agricultural products and byproducts.

“There’s tons of biomass grown by farms or farmers, and each of them has a special structure,” he said. “Eggshells are just an example. There’s lots of things we’re interested in that are grown by farms or farmers.”

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