Science Scene - Molten Metal Batteries

Molten metal batteries may be the future for larger grid-scale batteries. MIT engineers have created devices that can provide up to 20 times as much current as lithium-ion batteries with the same electrode area. The new battery simply consists of tanks filled with three liquid layers kept at 1,292 degrees F (700 degrees C). Molten magnesium sits on top, and antimony sits on the bottom (picture to left is similar design but uses sodium sulfer for the electrodes). The middle layer consists of a compound mixture of the two outer layers.
Charging the battery with electricity breaks down the middle layer, and thus enlarges the upper and lower layers, while discharging reverses the process, in a chemical reaction that releases electrons to provide power. Once running, the battery also creates enough self-sustaining heat to keep everything molten.
A battery as large as a shipping container could deliver a megawatt of electricity, or enough to power about 10,000 100-watt light bulbs for several hours. Its cheaper material costs compared to lithium make it a more cost-effective candidate for scaling up the power grid. The molten metal battery technology could provide part of a newer energy infrastructure that supports a growing variety of renewable energy sources.

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