New chemistries found for liquid batteries: Donald Sadoway, MIT Professor

New chemistries found for liquid batteries: Donald Sadoway MIT Professor

The Massachusetts Institute of Technology has found 'New Chemistries for Liquid Batteries'. Liquid metal batteries, invented by MIT professor Donald Sadoway and his students a decade ago, are a promising candidate for making renewable energy more practical. The batteries, which can store large amounts of energy and thus even out the ups and downs of power production and power use, are in the process of being commercialized by a Cambridge-based startup company, Ambri.

A paper by Sadoway in the journal Nature Communications the latest findings are reported. The have found that calcium, an abundant and inexpensive element, can form the basis for both the negative electrode layer and the molten salt that forms the middle layer of the three-layer battery.

Sadoway says, "It was the most difficult chemistry", as making calcium work in a battery was impossible. Another problem faced by the team was the high melting point of calcium which forced the liquid battery to work at 900 degree Celsius.

Sadoway and his team resolved both the problems. First they have tackled with the temperature related problem by alloying calcium with inexpensive metal magnesium. Thus resulting to lower operational temperature of 300 degree Celsius.

Second, they used salt in the battery's middle layer, the electrolyte that carries ions. The migration of those ions is accompanied by an electric current flowing through wires that are connected to the upper and lower molten metal layers, the battery's electrodes.

Solving problems led to surprises. Researchers found that multiple ions in the molten-salt electrolyte contribute to the flow, boosting the battery's overall energy output. "That was a totally serendipitous finding that could open up new avenues in battery design" said Sadoway.

"There's a whole level of supply-chain optimization that people haven't thought about," he says.

Sadoway says, as time passes, people can explore more parts of the periodic table" to find ever-better formulations.