MIT is definitely a hot spot on the map of green innovation. Besides making a major breakthrough in hydrolysis catalysis this past summer, MIT has delivered many good technology concepts lately, such as power-generating shock absorbers, solar race cars and even self-propelling fish farms, just to name a few. The latest MIT idea comes from its materials chemistry department, where a professor has demonstrated a new kind of battery.
A conventional battery consists of two solid metal electrodes immersed in an electrolyte that is touching them both. As they react over time, electrons travel through the electrolyte as well as through the load. This battery uses liquid electrodes instead. Three liquids are poured into a vessel – molten magnesium, molten antimony and an electrolyte. Due to their different densities, the three liquids naturally separate; the antimony settles to the bottom, the electrolyte rests in between and the magnesium sits on top.
As the battery discharges, the molten metals react and slowly ionize, dissolving into the electrolyte solution. Thus, when discharged, the battery is mostly electrolyte, with only thin layers of metal remaining. When it is recharged, the magnesium ions are reduced and the antimony ions are oxidized – which, in this case, causes both the magnesium and antimony to go from ionic to metallic form. Thus, the recharged battery once again has thick liquid metal layers and a thin electrolyte layer.
This might not be more than an interesting chemistry experiment, were it not for the fact that such a liquid battery offers numerous advantages over conventional ones. The liquid metals and molten salt (used as the electrolyte) can absorb very high electrical currents – ten times higher than the best batteries we have today, according to the MIT professor heading the project. And the design of the battery allows it to be built quickly and cheaply (the team only used magnesium and antimony for the prototype - they have found better, cheaper materials to use for real-world versions, but are keeping the details quiet).
In other words, these batteries could be ideal for solar power storage. If so, they would be welcomed with open arms – solar proponents know that the biggest thing standing in the way of large, utility-scale solar power is the question of how it can be effectively stored. We don’t yet have any really promising answers to that question. Solar power can drive hydrolysis and generate hydrogen gas to be used as fuel, but it can be inefficient. Some have proposed to pump water up hills so that it can power turbines on the way down, but if you’re short on water, that isn’t the best option. And ultracapcitors are still a little way off.
MIT, keep ‘em coming.
Via MIT Tech Review
written by SolarLad, March 06, 2009
written by Fred, July 16, 2009
written by Thomas, March 24, 2010
|< Prev||Next >|