Molten Salt Batteries

A big hurdle for renewable energy advancement is the lack of the kind of battery capacity needed to store enough power to supply power grid systems. For grid-scale power storage, the performance and weight benefits of lithium batteries are not useful. To power cities, these batteries need to be cheap and reliable, with the ability to last and withstand the demands of modern power consumption.

Molten salt batteries are not a new idea, they have been around for 50 years, but suffered from certain critical issues in the past. Commonly made from sodium with either sulfur or nickel chloride, the electrodes in these batteries are kept at very high temperatures, allowing for easy transfer of charge between the molten elements.

The problem was the ceramic membranes separating the electrodes. The membrane acts as a sieve allowing only molecules of a certain size to pass through. Ceramic membranes are too brittle and often shatter, making the system a less-than-ideal candidate for grid-level storage and distribution.

However, an MIT team has recently pioneered a new membrane system, which uses commonplace steel mesh coated with titanium nitride. This membrane is far more durable, as well as being cheaply and simply assembled. THese new membranes sort molecules through electrical reactivities instead of size, but the results are the same. The new membranes could put the molten salt battery back on the table for large-scale power storage As well as creating a bigger market for renewables like wind and solar.