In ‘The Missing Link to Renewable Energy’, MIT Prof., Donald Sadoway, wants to inspire us to invent our way out of the current energy crisis.
“If we’re going to get this country out of its current energy situation, we can’t just conserve our way out. We can’t just drill our way out. We can’t bomb our way out. We’re going to do it the old-fashioned, American way. We’re going to invent our way out, working together.”
Storage is one of the big challenges for the viability of renewable energy sources. Effective, affordable, scalable storage is the answer to what happens when the sun isn’t shining, the wind isn’t blowing or the waves are becalmed.
Electricity can be stored, batteries are not new. The challenge is the affordable and scalable part.
In professor Sadoway’s words, we need a storage system which is dirt cheap and huge. It won’t be dirt cheap if it needs precious metals and other expensive raw materials.
Donald Sadoway and his team propose a liquid metal battery as a solution to affordable, scalable storage. The inspiration came from the scalability of the the chemistry involved in the Hall-Héroult method of producing aluminum, invented in 1886.
The breakthrough moment came with the choice of metals. Prof. Sadoway chose not to look for the “coolest chemistry” and then hope to find a way to get the price low enough. He decided to aim the solution at the necessity for huge capacity at exceptionally low cost. So he went to the periodic table to search for an opposite pair of earth abundant, cheap metals.
The first modern battery was built by Alessandro Volta in 1800 and in many ways the chemistry is still the same. In this case an alternating pile of zinc and silver plates separated by card soaked in brine. To this day one the words for a battery in Latin languages is ‘pile’.
So, salt (in the case of the new liquid metal battery, molten salt) is fine. Zinc and silver are out of the question. Prof. Sadoway’s excitement at finding his “dirt cheap” alternative is still palpable. He fixed on magnesium and antimony. That was the theory and so follows the development. They got it to work and began the job of scaling the size and capacity. So far so good, but there is a long way to go. Prof. Sadoway and his colleagues have formed a company to develop the new technology, so let us wish them luck and look forward to the results.