“Today’s lithium-ion batteries are still too expensive for most such applications and contain a flammable electrolyte. So researchers started looking for cheap, Earth-abundant metals that might be able to substitute for lithium. After a search and some trial and error, they settled for aluminum and sulfur as its two electrode materials, with an electrolyte of molten chloro-aluminate salt in between. All these ingredients are cheap, readily available, and not flammable, which means there is no risk of fire or explosion.”
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“The chloro-aluminate salt they chose “essentially retired these runaway dendrites, while also allowing for very rapid charging,” says MIT Professor Donald Sadoway, one of the authors of the study describing the design. “We did experiments at very high charging rates, charging in less than a minute, and we never lost cells due to dendrite shorting.”