With the build-up of large wind and solar power systems, the need for economical, scalable backup solutions to provide power when the wind is calm and the sun is down is growing fast. The lithium-ion batteries currently used are too expensive for most such applications, and alternatives such as pumped hydro requires specific topography that is always not available.
In a new development, researchers at MIT and other institutions have developed a new kind of battery, composed completely from abundant and inexpensive materials, which could serve the purpose.
The new battery architecture is described in a paper in Nature.
The objective was to invent something that was much better than lithium-ion batteries for small-scale static use, and ultimately for automotive use.
Besides high cost, lithium-ion batteries contain a flammable electrolyte, which make them less than ideal for transportation. This led the researchers to study the periodic table, in a bid to find cheap, abundantly available metals to substitute lithium.
In fact, commercially dominant metal, iron, does not have the required electrochemical properties for an efficient battery, stated the lead researcher. But the second-most abundant metal available commercially, which is also the most abundant metal on earth, is aluminium.
The question following this what to pair aluminium with for the other electrode, and what kind of electrolyte to use in between to transport ions to and fro during charging and discharging. Sulfur is the most inexpensive among all non-metals, and thus became the second electrode material.
For the electrolyte, researchers refrained from using volatile, flammable organic liquids that have sometimes led to hazardous fires in cars and other applications of lithium-ion batteries. Some polymers were tried, but, at the end, variety of molten salts were looked at.