The B2B platform for full-electric and plug-in hybrid electric vehicles: Industry News

After most recent news about nickel-lithium batteries being three times better than li-ion, researchers at the Arizona State University might already dwarf these prospects by announcing a battery with 11 times the energy density of a lithium-ion battery at one-third the costs. The Metal-Air Ionic Liquid technology is supported by a 5 million US dollar research grant.

A University spin-off, namely Fluidic Energy, is testing a new battery technology that could have 11 times the energy density of a li-ion battery, while only costing less than one third and prolonging the battery life at the same time. Backed-up by a research grant from the US Department of Energy of about $5.13 million (around €3,4 million) the chances are pretty good to turn this ultra-dense energy storage technology into a reality.

Cody Friesen, a professor of materials science at Arizona State and founder of Fluidic Energy, said that the use of ionic liquids overcomes many of the problems that have held back metal-air batteries in the past. "I'm not claiming we have it yet, but if we do succeed, it really does change the way we think about storage," he added.

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Using ionic liquids as its electrolyte is the key of the new battery technology. The previous electrolytes used for metal-air batteries were water-based and caused therefore problems as the water evaporated and the batteries tended to fail prematurely. Another problem is that water has a relatively low electrochemical window, meaning it will begin to decompose when the cell exceeds 1.23 volts.

Ionic liquids that are used in the new Metal-Air Ionic Liquid batteries are salts that are a liquid at room temperature. The main advantages of ionic liquids are their non-volatility. In addition, they do not evaporate, they are physically stable, and they conduct electricity fairly well.

For the metal-air batteries it means first that they can function for a longer period time due to the non-evaporating electrolyte. Secondly, material with a greater energy density than for example zinc can be used thanks to its better electrochemical stability. And finally metal-air battery using an ionic liquid as its electrolyte would function significantly longer since drying out is no longer a problem.

Having electrochemical stability windows of up to five volts, that allows to go to much more energy-dense metals, the research team will target energy densities of at least 900 watt-hours per kilogram and up to 1,600 watt-hours per kilogram.

“This would mean that energy storage would no longer be a limiting factor for renewable energy, and electric vehicles that could travel 400 to 500 miles on a single charge at a cost just a little over lead-acid batteries," Friesen said.