Ambri liquid metal storage for Solarcity and supercharging stations

Short news article (written in November 2013) that embeds the above TED talk (which was given in March 2012):
MIT Battery Startup Ambri Finds Early Customer and Christens Factory : Greentech Media

This guy and his TED talk was mentioned a couple years ago on the forum -- TMC: The Smart Grid

The company is still active, raised a $35MM Series C funding round in April 2014: Ambri - News

The battery fits into a more general category of Molten salt battery (Wikipedia), except in this case the metals are kept in the liquid state as well.

Basic concept: pick your two dissimilar metals to be common/cheap and have different densities when molten (in this case, magnesium and antimony), so that one floats to the top and the other stays at the bottom. Then use a molten salt electrolyte with density between those of the metals to separate the layers. The energy lost to heat as the battery is charging/discharging is secondarily useful, as it works to keep its components in the liquid state.

No new/big news in the last couple of years.

It's not very applicable to distributed or home storage though -- the economies of scale needed to make it cheap would be lost at small sizes, not withstanding the safety issues of maintaining a vat of molten metal in your basement/garage.