Arizona State University (ASU) and Fluidic Energy, a spinoff company of ASU, have recently received funding from the U.S. Department of Energy (DOE) in the amount of $5.13 million to research and develop a metal-air battery that could dramatically outperform the best lithium-ion batteries on the market.
The Metal-Air Ionic Liquid (MAIL) battery program aims to create a battery that is measurably safe, earth-abundant and geo-politically sustainable, ultra-high energy density and low cost. The MAIL batteries will have unparalleled safety according to ASU because the oxidant and reductant are not stored in the same space, so the risk of catastrophic energy release and fire is non-existent in the event of an electric vehicle (EV) crash.
Metal-air batteries usually rely on water-based electrolytes and oxygen from ambient air that is drawn into the battery through a porous “air” electrode. A chemical reaction occurs when the oxygen contacts the electrolyte and produces hydroxyl ions. These ions reach the anode and begin to oxidize zinc, which produces current through the release of electrons. However, a barrier to using these batteries has been that the water-based electrolyte can evaporate.
Cody Friesen, Ph. D., the primary investigator of the MAIL research and director of the Center for Renewable Energy Electrochemistry at ASU, says a metal-air battery using an ionic liquid as its electrolyte functions significantly longer because drying out is no longer a problem, and it gets a big boost in energy density relative to the same metal-air battery using a water-based electrolyte.
“These liquids have electrochemical stability windows of up to five volts, so it allows you to go to much more energy-dense metals than zinc,” explained Friesen.
Another problem with rechargeable batteries is that over time they experience dendrite growth on the electrodes after successive charges. These dendrites can limit the number of charging cycles and decrease the lifetime of the battery. Fluidic energy has designed a porous electrode scaffold that will overcome dendrite formation and give the batteries a considerably longer life span.
Having overcome these limitations to metal-air batteries, “we’re working now on taking it to the next level,” said Friesen. “It’s about taking everything we’ve done over the last four years and leveraging that work into a battery that looks and feels just like a lithium battery but has energy densities far beyond that.”
If successful, the research team hopes to produce a battery that could power an EV for up to 400 or 500 miles on a single charge at a cost comparable to lead acid batteries used today.