Engineers at MIT have come up with a new battery design created with common materials – aluminum, sulfur, and salt. The battery is low-cost and resistant to fire and failures. It can be charged very fast, which could make it useful for powering a home or charging electric vehicles.
Lithium-ion batteries have been the most used batteries for the last few decades due to their reliability and high energy density. However, lithium is becoming scarcer and more expensive, and the cells can be dangerous, exploding or bursting into flames if damaged or improperly used.
After a search and some trial and error, the team from MIT settled on aluminum for one electrode and sulfur for the other, topped off with an electrolyte of molten chloro-aluminate salt. These materials are more economical and safer.
The team proved with their tests that the new battery cells could tolerate hundreds of charge cycles, and charge very quickly – in some experiments, less than a minute. The cells would cost just one-sixth of the price of a similar-sized lithium-ion cell.
They can not only operate at high temperatures of up to 200 °C (392 °F) but they work better when hotter – at 110 °C (230 °F), the batteries charged 25 times faster than they did at 25 °C (77 °F). The battery doesn’t need any external energy to reach this elevated temperature.
The salt in the electrolyte has a low melting point and has another benefit of preventing the formation of dendrites. These metal tendrils, which gradually grow between the two electrodes until they cause a short circuit, are a major hurdle for batteries, particularly lithium-ion cells.
The team says that this battery design would be best suited to the scale of a few dozen kilowatt-hours, like powering an individual home from renewable sources. They could also be useful as charging stations for electric vehicles, thanks to their rapid charging.
The patents for the aluminum-sulfur batteries have been licensed to a spinoff company called Avanti, co-founded by one of the authors of the study describing the design.
The research was published in the journal Nature.