Ambri’s CTO, David Bradwell (left), helped invent the first small-scale liquid-metal battery while a graduate student in the MIT lab of Donald Sadoway, who conceived of a design inspired by aluminum smelters.


Ambri’s Better Grid Battery

A tiny startup called Ambri wants to transform our energy system with massive liquid-metal batteries.

By Martin LaMonica on February 18, 2013

Standing next to the Ping-Pong table in the offices of the battery startup Ambri, chief technology officer David Bradwell needs both hands to pick up what he hopes will be a building block for a new type of electricity grid. Made of thick steel, it’s a container shaped like a large round cake pan, 16 inches in diameter. Inside it are two metal pucks and some salt powder; a round plate has been welded to the top to make a 100-pound battery cell.

By stringing together a number of these large cells, Ambri plans to make huge batteries, as big as 40-foot shipping containers. It’s not only their size that makes them novel: the chemistry in Ambri’s technology is different from any other currently used in batteries. When the cell is heated to around 500 °C, the disks and powder inside—the battery’s electrodes and electrolyte, respectively—will melt. The result is a battery whose components are all liquid. Conventional rechargeable batteries have solid electrodes that degrade with use, but a battery with only liquid parts could last for years without losing much of its energy storage capacity. The molten materials can also operate at much higher current densities than solids, and for longer periods of time.

Read more: Ambri’s Better Grid Battery | MIT Technology Review.

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