Molten-Air Batteries Might Give EVs 7,000 Miles Range

Some automakers are investing a lot into creating fuel cell vehicles, but unless they don’t come up with a very cheap way to get hydrogen, standard electric vehicles seem a better alternative transport solution. And scientists now also created a new type of battery that might cure the range anxiety by hundreds of miles.
molten-air battery prototype 1 photo
Photo: George Washington University
At the moment, EVs are limited by their range and high recharging time because of the lithium-ion batteries’ limited energy density. For a quick example, gasoline has an energy density of around 12.8 kWh/kg. Of course, that can’t be all used since combustion engines have a thermal efficiency of around 34 percent, but it’s still a heck of a lot compared to the energy density offered in, say the average Nissan Leaf battery of 120 Wh/kg (note that these are just Watt-hour per kg and not kilowatt-hour per kg).

Which translates into a total of 24 kWh for the Leaf’s battery pack and around 550 kWh for your average full gasoline tank. Include the engine efficiency factor and you’ll end up with around 187 kWh usable energy from the gas tank, but that is still 7 times more than what your average EV offers.

Leaving aside the boring calculus part, the researchers at George Washington University might have just created a solution for electric range anxiety - molten air batteries.

These new type of rechargeable batteries are using molten electrolytes, oxygen from the air and “multiple electron” storage electrodes such as iron, carbon or vanadium boride. This enables the new batteries to be around 11 to 50 times more energy dense than the current lithium-ion ones.

Which means your Nissan Leaf could get an autonomy of around 7,000 miles (11,265 km). Some people might not even need to recharge it for six months.

For such thing to work, the oxygen is used directly from the surrounding air, which gives the battery a high capacity, while the electrolytes are melted to a liquid state at temperatures of around 700 - 800 degrees Celsius. The high temperature is currently the big gap that separates the molten-air battery concept from the production version.

Such temperatures are obtained in current combustion engines so it doesn’t seem that strange to think there is lava under your hood, but what will keep the battery in that hot state seems to be the mystery here.

Either they succeed to create a viable unit to be fitted in electric vehicles or not, let’s not forget about those dual carbon batteries that seem a much more feasible project.
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