Very thin: "Sadoway, who is also the John F. Elliott professor of materials chemistry at Massachusetts Institute of Technology, wouldn’t say what

Very thin: "Sadoway, who is also the John F. Elliott professor of materials chemistry at Massachusetts Institute of Technology, wouldn’t say what goes into liquid-metal batteries." Here's a description from an earlier article -- same idea with different materials: "After hitting upon the idea of the liquid-metal battery, ­Sadoway searched for the perfect electrodes: he ended up choosing magnesium and antimony because they are cheap and separate naturally when in liquid form, the lighter magnesium rising to the top. A liquid-salt electrolyte rests between the magnesium and antimony electrodes, creating a cell with three layers." http://www.technologyreview.com/featuredstory/511081/am http://www.technologyreview.com/featuredstory/511081/am So it's a chemical battery where the electrodes are liquids. (FWIW: Magnesium melts at 650 °C).