The problem that still impedes a wider use of renewable energy sources is their dependence on uncontrollable factors. A solar panel does not give energy at night, while a wind turbine only spins if the wind is blowing. And storing this energy is still very expensive.
A gigantic battery-like hydropower plant was inaugurated in Switzerland last month, but that only works in specific situations. For a wider solution, researchers at MIT, along with colleagues from China, Canada, Kentucky and Tennessee, are proposing an aluminium-sulphur battery which could provide affordable storage for renewable energy.
The scientists have discovered a new way of making batteries for the storage of renewable energy. The batteries, still in the concept phase, are made from abundant, thus inexpensive materials, being based on aluminium, sulphur and rock crystals, rather than lithium-ion.
As the world builds out ever larger installations of wind and solar power systems, the need is growing fast for economical, large-scale backup systems to provide power when the sun is down and the air is calm.
MIT News
The aluminium and sulphur are used as the two electrode materials, while the electrolyte in between is made out of molten salt crystals. “I wanted to invent something that was better, much better, than lithium-ion batteries for small-scale stationary storage, and ultimately for automotive”, said Professor Donald Sadoway, the John F. Elliott Professor Emeritus of Materials Chemistry at MIT.
Professor Sadoway explained that he started the project by looking at the periodic table in search of a cheap, easily accessible and abundant metal that could relace the lithium currently used in batteries. He soon found out that aluminium is not only the most abundant metal on earth, but also the second-most-abundant metal in the marketplace. “So, I said, well, let’s just make that a bookend. It’s gonna be aluminium”, he revealed.
He then looked for the cheapest non metal to pair the aluminium with, which is sulphur. For the electrolyte, he looked for various salts with low melting points, almost as low as 100˚C, which is important so batteries to not require any special insulation and anticorrosion measures.
The ingredients are cheap, and the thing is safe — it cannot burn.
Professor Donald Sadoway, researcher at MIT
Addressing concerns over the known horrible smell of sulphur, Professor Sadoway said there is nothing to worry about, as the material is locked inside the battery cells. ” The rotten-egg smell is in the gas, hydrogen sulphide. This is elemental sulphur, and it’s going to be enclosed inside the cells”, he explained.
“If you were to try to open up a lithium-ion cell in your kitchen, the moisture in the air would react and you’d start generating all sorts of foul gases as well. These are legitimate questions, but the battery is sealed, it’s not an open vessel. So I wouldn’t be concerned about that”, he added.
