Researchers improve liquid batteries

Researchers have succeeded in significantly improving molten metal-based batteries, moving closer to the deployment of energy from renewable sources. The batteries largely retain their capacity, even after ten years of charging and discharging.

The researchers at MIT’s Department of Materials Chemistry use two layers of molten metal for their battery: one electrode made of lithium and one made of a mix of lead and antimony. The layers are separated by a layer of molten salt, which acts as an electrolyte. Due to the difference in density, the three layers are separated automatically.

The battery is a variant of an earlier version, with magnesium for one electrode and antimony for the other. The advantage of the new version is that it functions at temperatures between 450 and 500 degrees Celsius instead of 700 degrees. This makes it easier to design usable batteries and the new formula is also cheaper to produce.

Tests show that the batteries can withstand ten years of charging and discharging cycles while retaining 85 percent of their original capacity. The technique can be used in particular for the storage of energy at sources with variable production and demand, such as hydroelectric power stations, wind turbines and solar panels. According to Donald Sadoways of the Materials Chemistry research group at MIT, great discoveries are still to be made for other combinations of metals, which can provide greater gains in temperature and cost.

Model of a liquid battery with the electrodes above and below and the electrolyte in the middle.