A Pinch of Salt Boosts Aluminum Batteries
taylorvich writes:
https://spectrum.ieee.org/aluminum-battery
This sustainable, solid-state electrolyte design outlives lithium-ion batteries
Electric vehicles( EVs) and green energy sources rely heavily on batteries to store electricity. Currently, more than 75 percent of the world's energy storage depends on batteries that contain lithium, an expensive mineral that's subject to volatile pricing. Lithium-ion (Li-ion) batteries themselves can be volatile, too, because they use a flammable electrolyte that can catch fire when overcharged.
Now, a group of scientists based in Beijing believes that aluminum offers a better solution. Aluminum is the third-most abundant mineral in the Earth's crust and costs about one-quarter as much as lithium. And if built right, aluminum-based batteries may offer longer life expectancy and a safer, more sustainable design than their volatile counterparts. Led by scientists from the Beijing Institute of Technology and the University of Science and Technology Beijing, the group has found a way to stabilize aluminum batteries that can last far longer.
Aluminum-ion (Al-ion) batteries have been the subject of research for years. But previous attempts have generally used ionic liquid electrolytes, which can lead to anode corrosion, especially in humid conditions. Other researchers have used gel polymer electrolytes, halfway between liquid and solid-state alternatives, but these tend to have low conductivity. This team of researchers took a different approach and added a pinch of salt-namely, an inert aluminum fluoride salt-to a liquid electrolyte containing aluminum ions, creating a solid-state electrolyte.
Well, more than a pinch of salt, really. The salt has a porous 3D structure, which allows it to act like a rigid sponge that absorbs and stabilizes the liquid, yet still allows the ions to move more freely. This increases conductivity of the material, and the result is a solid composite material that cannot leak. The researchers also coated the electrodes with a thin layer of material that helps prevent crystals of aluminum from forming, which would degrade battery performance over time.
"Our research shows that a stable, recyclable solid-state electrolyte can improve aluminum-ion batteries by solving issues like corrosion, safety, and long-cycle life, making them a potential alternative to lithium-based batteries," says Shuqiang Jiao, a professor of electrochemical engineering at the University of Science and Technology Beijing.
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