New combination of materials creates record-breaking lithium-metal cell
Currently, lithium-ion batteries are the most prevalent solution for mobile power supply. In some applications, however, it reaches its limits.
This especially holds for electric mobility, where lightweight and compact vehicles with large ranges are desired. Lithium-metal batteries may be an alternative. They are characterized by a high energy density, meaning that they store much energy per mass or volume. Still, stability is a problem, because the electrode materials react with conventional electrolyte systems.
Researchers of Karlsruhe Institute of Technology (KIT) and the Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU) have now found a solution. As reported in Joule, they have used a promising new combination of materials.
A cobalt-poor, nickel-rich layered cathode (NCM88) reaches a high energy density. With the usually applied, commercially available organic electrolyte (LP30), however, stability leaves a lot to be desired. Storage capacity decreases with an increasing number of cycles.
Professor Stefano Passerini, Director of HIU and Head of the Electrochemistry for Batteries Group, explains the reason: “In the electrolyte LP30, particles crack on the cathode. Inside these cracks, the electrolyte reacts and damages the structure.
In addition, a thick mossy lithium-containing layer forms on the anode.” For this reason, the scientists used a non-volatile, poorly-flammable, dual-anion ionic liquid electrolyte (ILE) instead. “With the help of ILE, structural modifications on the nickel-rich cathode can be reduced significantly,” says Dr. Guk-Tae Kim from the Electrochemistry for Batteries Group of HIU.
Capacity 88 percent after 1000 cycles
The results: The lithium-metal battery with the NCM88 cathode and the ILE electrolyte reaches an energy density of 560 watt-hours per kilogram (Wh/kg)—based on the total weight of the active materials. Its initial storage capacity is 214 milliampere hours per gram (mAh g-1) of the cathode material.
After 1000 cycles, 88 percent of the capacity are retained. The average Coulombic efficiency, i.e., the ratio between discharge and charge capacity, is 99.94 percent. As the battery is characterized by a high safety, the researchers have made an important step towards carbon-neutral mobility.
See more here: phys.org
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Howdy
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“Capacity 88 percent after 1000 cycles”
This could easily be exceeded in less than 12 months of use. Instead of chasing energy density purely, how about longevity without needing to carry more cells than strictly necessary to reduce depth of discharge?
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D. Boss
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Don’t be silly! If your EV goes 150 miles per charge, then 1,000 charge cycles is 150,000 miles driven! This is about the lifespan of an internal combustion engine! And how many people do you know, aside from taxi drivers who drive 150,000 miles a year?
My position is EV’s are stupid, but you can’t make dumb arguments against them! A better argument is even with 560 Wh/kg they are still far lower energy density than gasoline. 560 Wh/kg is 2.02 MJ/kg.
Gasoline has 46 MJ/kg, and petrol cars are on average about 25% efficient, so the net useful energy you get from burning gasoline is 11.5 MJ/kg. So gasoline has 5.7 times more useful energy stored per kilogram than do these new batteries!
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Howdy
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“Don’t be silly! If your EV goes 150 miles per charge, then 1,000 charge cycles is 150,000 miles driven! This is about the lifespan of an internal combustion engine!”
I never mentioned an EV did I? Plus range is dependent on far more than the vehicle, with some only getting 60 miles to a charge. Further, the range decreases as the battery ages.
But for me to use an EV for work all day means several recharges per day. Whether that use is stop-start driving in town, or motorway use, as well as temperature and weather conditions, will make a massive difference.
Should I want, or need to get to the capital of the country I live in and my EV gets 150 miles on a charge as you claim, I’m looking at minimum, 7 recharges to get there and back, on top of the initial charge I started out with. which leaves little to no reserve capacity. This is what degrades the cells quickly, which is where depth of discharge comes in.
Whether I know anybody who drives 150 thousand miles a year or not is moot. The fact is, people do it.
Not silly at all.
Engines last a lot longer than 150,000 miles unless one doesn’t do maintenance or drives with no driver sympathy. The USA is a good example of vehicles with very high mileages.
http://www.subaruhighmileageclub.com/miles500000.html
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Joseph Olson
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more meaningless “laboratory” parlor tricks in controlled conditions….ignore real world thermal and vibration shocks….ignore rare element and manufacturing costs….get massive DOE grants for jumping through hypothetical hoops….government “faux science” is a fraud
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T.C. Clark
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There is always a new battery tech out there…always. How much does it cost? Lithium batteries are now in the boat world. I have seen a picture of a solar powered yacht….not a handsome boat with a huge solar array on a catamaran type hull. Some yachts advertise their ability to only run a generator an hour per average day to charge the batteries. World must have an inexhaustible lithium supply.
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Eric the Red
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I’m sure the thought of these improved batteries will give immense comfort to the owner as their vehicle spontaneously erupts into uncontrollable flames.
But that’s all ok anyway, as the government in its infinite wisdom has remotely switched off your ability to drive that day, because it’s an odd day of the week or whatever, and we all must do our part to save the planet from whatever is the current ongoing crisis.
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