Date:14th Feb 2012
Magnesium and Antimony based low cost
batteries researched by MIT
Researchers at MIT are working on high temperature batteries
using molten materials to form the positive and negative
poles of the battery, as well as a layer of electrolyte.
Material selection is the important factor the researchers
are working on, looking for the materials that are abundant
and inexpensive. One such combination suggested is magnesium
for the negative electrode (top layer), a salt mixture containing
magnesium chloride for the electrolyte (middle layer) and
antimony for the positive electrode (bottom layer). The
system would operate at a temperature of 700 degrees Celsius,
or 1,292 degrees Fahrenheit.
Donald Sadoway, the John F. Elliott Professor of Materials
Chemistry at MIT explains, "The battery delivers current
as magnesium atoms lose two electrons, becoming magnesium
ions that migrate through the electrolyte to the other electrode.
There, they require two electrons and revert to ordinary
magnesium atoms, which form an alloy with the antimony.
To recharge, the battery is connected to a source of electricity,
which drives magnesium out of the alloy and across the electrolyte,
where it then rejoins the negative electrode."
On the cost factor of the battery Sadoway explains "don't
care what the stuff is made of, or what the size is. The
only question is what's the cost of storage" for a
given amount of power. "I can build a gorgeous battery
to a NASA price point," he says - but when cost is
the primary driver, "that changes the search"
for the best materials. Just based on the rarity and cost
of some elements, "large sections of the periodic table
are off limits."
These batteries are designed for storing power from renewable
energy sources such as Solar PV, Wind.