Slashdot reader sciencehabit shares Science magazine’s look at efforts to transform zinc batteries “from small, throwaway cells often used in hearing aids into rechargeable behemoths that could be attached to the power grid, storing solar or wind power for nighttime or when the wind is calm.”
With startups proliferating and lab studies coming thick and fast, “Zinc batteries are a very hot field,” says Chunsheng Wang, a battery expert at the University of Maryland, College Park. Lithium-ion batteries — giant versions of those found in electric vehicles — are the current front-runners for storing renewable energy, but their components can be expensive. Zinc batteries are easier on the wallet and the planet — and lab experiments are now pointing to ways around their primary drawback: They can’t be recharged over and over for decades.
For power storage, “Lithium-ion is the 800-pound gorilla,” says Michael Burz, CEO of EnZinc, a zinc battery startup. But lithium, a relatively rare metal that’s only mined in a handful of countries, is too scarce and expensive to back up the world’s utility grids. (It’s also in demand from automakers for electric vehicles.) Lithium-ion batteries also typically use a flammable liquid electrolyte. That means megawatt-scale batteries must have pricey cooling and fire-suppression technology. “We need an alternative to lithium,” says Debra Rolison, who heads advanced electrochemical materials research at the Naval Research Laboratory. Enter zinc, a silvery, nontoxic, cheap, abundant metal. Nonrechargeable zinc batteries have been on the market for decades. More recently, some zinc rechargeables have also been commercialized, but they tend to have limited energy storage capacity. Another technology — zinc flow cell batteries — is also making strides. But it requires more complex valves, pumps, and tanks to operate. So, researchers are now working to improve another variety, zinc-air cells…
Advances are injecting new hope that rechargeable zinc-air batteries will one day be able to take on lithium. Because of the low cost of their materials, grid-scale zinc-air batteries could cost $100 per kilowatt-hour, less than half the cost of today’s cheapest lithium-ion versions. “There is a lot of promise here,” Burz says. But researchers still need to scale up their production from small button cells and cellphone-size pouches to shipping container-size systems, all while maintaining their performance, a process that will likely take years.
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