A group of researchers from MIT is working on a method of designing large, eco-friendly, stationary batteries that are made entirely from liquid metal and would be capable of storing enormous amounts of power.

The liquid batteries are being eyed as potential storage mediums for power generated by wind farms or solar cells and may one day serve as backup power systems for hospitals. Hospitals today relay on massive generators for power in emergencies.

One of the MIT researchers, Don Sadoway, said, "Since these batteries won't be in someone's hand or in a car, we don't have to make them crash-worthy, idiot-proof, and it doesn't have to operate at around body temperature."

The battery Sadoway and his team have developed has no solid materials in them from the electrodes, membranes and any other parts of the battery. The anode, cathode, and membrane of the battery designed by the team are all made from molten liquids.

The team has tried many different combinations of liquids over the years in the battery. One of the first liquid metal combinations tried was molten antimony and magnesium with sodium sulfide between the two to store energy.

The layers of the battery won't mix because each layer has a different weight, rather like mixing oil and water in a glass and watching the layers separate back out after mixing. The specific composition of the battery the team is currently working on is a secret.

The battery is encased in stainless steel and is reported to have to maintain a temperature of 500 degrees to keep the metals inside in liquid form. The final size of the battery has not yet been determined.

Sadoway says, "This should be easy to scale up. If we want to make a battery the size of a 33 gallon garbage can we can do it. If we want to make [a battery] the size of a football field we could do it."

The liquid metal batteries would require about the same safety precautions as a standard household oven reports MSNBC. Fully liquid metal batteries are expected to replace molten liquid batteries at some point.

Battery expert Marca Doeff from the Lawrence Berkeley National Laboratory said, "This is still a conceptual idea. There are still engineering challenges that need to be overcome." The researchers believe that liquid metal batteries are still years away from reality.