MIT’s new aluminum-sulfur batteries could provide low-cost storage for renewable energy

The devices are made of cheap and abundant materials.
Loukia Papadopoulos
The three ingredients used in MIT's batteries.jpg
The three ingredients used in MIT's batteries.

MIT/Rebecca Miller 

Renewable energy is great, but what do you do when the sun doesn't shine, or the wind does not blow? You could use lithium-ion batteries but they are expensive and contain a flammable electrolyte, making them less than ideal for transportation as they run a fire risk.

However, there may be a solution on the way. A Massachusetts Institute of Technology (MIT) professor called Donald Sadoway, along with 15 others at MIT and in China, Canada, Kentucky, and Tennessee, has released a new paper demonstrating an aluminum-sulfur battery that may just replace lithium-ion ones and be the key to storing renewable energy, according to a statement by the institution published on Wednesday.

Much better than lithium-ion batteries

“I wanted to invent something that was better, much better, than lithium-ion batteries for small-scale stationary storage, and ultimately for automotive [uses],” explained Sadoway, who is the John F. Elliott Professor Emeritus of Materials Chemistry.

To do this, he looked at the periodic table for a cheap, Earth-abundant, and easily accessible metal that could safely and reliably replace lithium. He noticed that the second-most-abundant metal in the marketplace — and actually the most abundant metal on Earth — was aluminum. “So, I said, well, let’s just make that a bookend. It’s gonna be aluminum,” he added.

He then decided to pair it with the cheapest of all the non-metals: sulfur. And finally, for the electrolyte, he went with a variety of molten salts that have relatively low melting points — close to the boiling point of water, as opposed to nearly 1,000 degrees Fahrenheit for many salts.

MIT’s new aluminum-sulfur batteries could provide low-cost storage for renewable energy
The batteries could make renewable energy truly viable.

“Once you get down to near body temperature, it becomes practical” to make batteries that don’t require special insulation and anticorrosion measures, he explained.

Combining these three elements together proved very successful. “The ingredients are cheap, and the thing is safe — it cannot burn,” Sadoway further added.

No external heat source required

Even better, the new battery requires no external heat source to maintain its operating temperature, as the heat is naturally generated by the charging and discharging of the battery.

“As you charge, you generate heat, and that keeps the salt from freezing. And then, when you discharge, it also generates heat,” Sadoway explained.

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In a typical installation used for load-leveling at a solar generation facility, for example, “you’d store electricity when the sun is shining, and then you’d draw electricity after dark, and you’d do this every day. And that charge-idle-discharge-idle is enough to generate enough heat to keep the thing at temperature.”

Sadoway and one of his students have already created a new spinoff company called Avanti which has licensed the patents for the new battery system. “The first order of business for the company is to demonstrate that it works at scale,” Sadoway concluded.

If it does indeed, then it could revolutionize how we approach energy storage and could make renewables truly viable.

Now, that’s something to get excited about!

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