Published on March 22nd, 2018 | by Tina Casey0
Energy Storage From Thin Air: You Ain’t Seen Nothing Yet
March 22nd, 2018 by Tina Casey
If you thought the energy storage market was all steamed up, fasten your seatbelt. A new research breakthrough from the University of Illinois at Chicago finally delivers some good news for fans of lithium-air technology, which energy storage researchers have been talking up as the next best thing to follow today’s gold standard, lithium-ion.
How much is next best? Lithium air is described as the lightest and most efficient energy storage technology available. Lithium air batteries could deliver five to ten times the energy density of lithium ion batteries — if someone could figure out how to get them to work.
Why Lithium-Air Energy Storage Is So Hard
Lithium air energy storage happens when lithium combines with oxygen in the air to form lithium peroxide, and back again. In other words, lithium peroxide is created when the battery discharges, and then broken back down into lithium and oxygen when the battery is charged.
Until now, though, the term “lithium-air” has been a bit of a misnomer. That’s because lithium-air batteries as configured currently don’t really use oxygen from the air, they use pure oxygen.
That creates problems when you’re trying to design a better battery for an electric vehicle. Unless you have a medical condition requiring oxygen, who wants to drive around with oxygen tanks in the back seat?
Here’s the explainer from the UIC, which worked with Argonne National Laboratory on the new battery research:
Unfortunately, experimental designs of such lithium-air batteries have been unable to operate in a true natural-air environment due to the oxidation of the lithium anode and production of undesirable byproducts on the cathode that result from lithium ions combining with carbon dioxide and water vapor in the air.
I know, right? As air enters the battery, the byproducts collect on the cathode, eventually rendering it useless.
A Better Lithium-Air Battery
For their new battery, the researchers came up with a new formula. The lithium anode is coated with a layer of lithium carbonate, which enables lithium ions to pass through without allowing other “unwanted compounds” to make contact.
The team also modified the spongy, carbon-based material for the cathode (that’s where air enters the battery, remember):
…Salehi-Khojin and his colleagues coated the lattice structure with a molybdenum disulfate catalyst and used a unique hybrid electrolyte made of ionic liquid and dimethyl sulfoxide, a common component of battery electrolytes, that helped facilitate lithium-oxygen reactions, minimize lithium reactions with other elements in the air and boost the efficiency of the battery.
Got all that? Basically, instead of tweaking the battery here, the team performed a “complete architectural overhaul.”
You can get all the details in the journal Nature, under the title, “Lithium-Oxygen Batteries with Long Cycle Life in a Realistic Air Atmosphere,” after the publication date of March 22.
Group Hug For New Energy Storage Technology
There’s still a way to go before the new battery passes from the lab to your new EV with the billion-mile range (slight exaggeration there — anything over 300 miles will do). So far, the battery has maintained its performance over 700 charging cycles, which is much better than previous attempts but still not quite up to snuff for road-ready purposes.
Meanwhile, researchers at Argonne are enthusing over their role in the new battery breakthrough, which consisted of conducted the computer studies validating the system’s performance.
UIC gets credit for everything else — building, testing, analyzing and characterizing the new energy storage technology — but the folks at Argonne want to make everyone, especially US taxpayers, aware that their/our fancy computers will “prove crucial” to further improvements in the technology:
Important to the project’s success was the use of the Argonne Leadership Computing Facility (ALCF) and the Center for Nanoscale Materials (CNM) for high-performance computing. The ALCF and CNM are DOE Office of Science User Facilities, both located at Argonne.
So, group hug for US taxpayers!
Speaking Of EV Battery Range…
While everyone is waiting around for the new lithium-air technology to bust through the laboratory walls, it’s helpful to keep in mind that longer range isn’t the only pathway for better EV performance.
Battery swapping is another option, at least for motorcycles, scooters, and e-bikes, though the idea seems to have fallen by the wayside when it comes to sedans and larger EVs. Better EV charging technology is also going to help push electric vehicles into the mainstream.
Solar cells, regenerative braking, and other onboard energy harvesting systems could also provide an extra boost for EV batteries. In one especially interesting twist, tire manufacturer Goodyear is proposing a new tire that deploys bio-energy from moss (yep, moss) to help run EV systems.
On the other hand, the current state of energy storage technology is already in shape to attract massive investment from major auto manufacturers (we mean other than Tesla, that is). In one of the latest developments, Volkswagen is sinking $25 billion into energy storage commitments with three leading battery firms, to support its plans for selling 3 million EVs yearly by 2025.
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Image: via UIC.