Ultra-fast charging aluminum battery offers safe alternative to conventional batteries

April 6, 2015
Stanford scientists have invented a flexible, high-performance aluminum battery that charges in about 1 minute. Credit: Mark Shwartz, Precourt Institute for Energy, Stanford University

Stanford University scientists have invented the first high-performance aluminum battery that's fast-charging, long-lasting and inexpensive. Researchers say the new technology offers a safe alternative to many commercial batteries in wide use today.

"We have developed a rechargeable aluminum that may replace existing storage devices, such as alkaline batteries, which are bad for the environment, and lithium-ion batteries, which occasionally burst into flames," said Hongjie Dai, a professor of chemistry at Stanford. "Our won't catch fire, even if you drill through it."

Dai and his colleagues describe their novel aluminum-ion battery in "An ultrafast rechargeable aluminum-ion battery," in the April 6 advance online edition of the journal Nature.

Aluminum has long been an attractive material for batteries, mainly because of its low cost, low flammability and high-charge storage capacity. For decades, researchers have tried unsuccessfully to develop a commercially viable aluminum-ion battery. A key challenge has been finding materials capable of producing sufficient voltage after repeated cycles of charging and discharging.

Graphite cathode

An aluminum-ion battery consists of two electrodes: a negatively charged anode made of aluminum and a positively charged cathode.

"People have tried different kinds of materials for the cathode," Dai said. "We accidentally discovered that a simple solution is to use graphite, which is basically carbon. In our study, we identified a few types of graphite material that give us very good performance."

For the experimental battery, the Stanford team placed the aluminum anode and graphite cathode, along with an ionic liquid electrolyte, inside a flexible polymer- coated pouch.

"The electrolyte is basically a salt that's liquid at room temperature, so it's very safe," said Stanford graduate student Ming Gong, co-lead author of the Nature study.

Stanford Professor Hongjie Dai's lab has invented an ultra-fast aluminum-ion battery with electrodes made of inexpensive aluminum (Al) and sheets of nanocarbon. Credit: Meng-Chang Lin & Hongjie Dai, Stanford University

Aluminum batteries are safer than conventional lithium-ion batteries used in millions of laptops and cell phones today, Dai added.

"Lithium-ion batteries can be a fire hazard," he said.

As an example, he pointed to recent decisions by United and Delta airlines to ban bulk shipments on passenger planes.

"In our study, we have videos showing that you can drill through the aluminum battery pouch, and it will continue working for a while longer without catching fire," Dai said. "But lithium batteries can go off in an unpredictable manner - in the air, the car or in your pocket. Besides safety, we have achieved major breakthroughs in aluminum battery performance."

One example is ultra-fast charging. Smartphone owners know that it can take hours to charge a lithium-ion battery. But the Stanford team reported "unprecedented charging times" of down to one minute with the aluminum prototype.

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Durability is another important factor. Aluminum batteries developed at other laboratories usually died after just 100 charge-discharge cycles. But the Stanford battery was able to withstand more than 7,500 cycles without any loss of capacity. "This was the first time an ultra-fast aluminum-ion battery was constructed with stability over thousands of cycles," the authors wrote.

By comparison, a typical lithium-ion battery lasts about 1,000 cycles.

"Another feature of the aluminum battery is flexibility," Gong said. "You can bend it and fold it, so it has the potential for use in flexible electronic devices. Aluminum is also a cheaper metal than lithium."

Applications

In addition to small electronic devices, aluminum batteries could be used to store renewable energy on the electrical grid, Dai said.

"The grid needs a battery with a long cycle life that can rapidly store and release energy," he explained. "Our latest unpublished data suggest that an aluminum battery can be recharged tens of thousands of times. It's hard to imagine building a huge lithium-ion battery for grid storage."

Aluminum-ion technology also offers an environmentally friendly alternative to disposable alkaline batteries, Dai said.

"Millions of consumers use 1.5-volt AA and AAA batteries," he said. "Our rechargeable aluminum battery generates about two volts of electricity. That's higher than anyone has achieved with aluminum."

But more improvements will be needed to match the voltage of , Dai added.

"Our battery produces about half the voltage of a typical lithium battery," he said. "But improving the cathode material could eventually increase the voltage and energy density. Otherwise, our battery has everything else you'd dream that a battery should have: inexpensive electrodes, good safety, high-speed charging, flexibility and long cycle life. I see this as a new battery in its early days. It's quite exciting."

Explore further: New imaging technique finds formation of aluminum alloys to blame for next-gen battery failures

More information: An ultrafast rechargeable aluminum-ion battery, DOI: 10.1038/nature14340

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45 comments

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Eikka
5 / 5 (5) Apr 06, 2015
For stationary applications, the energy density is not an issue, as long as it's somewhat reasonable.

Too bad the journal reference link is broken. I'd like to find more about it.
Jimee
5 / 5 (2) Apr 06, 2015
Get after it!
bearly
3 / 5 (4) Apr 06, 2015
The article gives all the specs except how long the battery will power various gadgets.
We need a battery that once charged will power, say a smart phone, for a week of continuous use.
Dethe
3.7 / 5 (3) Apr 06, 2015
They did use 1-ethyl-3- methylimidazolium chloride [EMIm]Cl / AlCl3 (40/60 mol.-%) electrolyte, similar one, which is already used for electrodeposition of aluminum layers from aqueous solutions. The resulting capacity is 85 Ah/kg (about half of one achieved with LiION batteries). Given the fact, that lithium is strategic metal for electromobility, this stuff looks pretty interesting.
SciTechdude
1 / 5 (1) Apr 06, 2015
It says it's about half as powerful as a standard lithium, and has a current max output of ~2v. So right now that's about as good as 1 AA battery, but probably about twice the size.
Dethe
1 / 5 (1) Apr 06, 2015
It depends on type of battery. The rechargeable lithium AA batteries tend to have lower capacity and also voltage, so you shouldn't compare the aluminum accumulators with non-recheargable battery.
Dethe
1 / 5 (4) Apr 06, 2015
We need a battery that once charged will power, say a smart phone, for a week of continuous use.
It also depends on gadget used. You shouldn't consider the Apple Watch or another mobile hand warmer, the supplementary function of which is to show something at display. Or you may want to wait for cold fusion thermoelectric batteries in Terminator T-100 style.
betterexists
2 / 5 (4) Apr 06, 2015
Utilizing Services of Foreigners, eh? Just use 2 Batteries side by side, Folks!
Sonhouse
4 / 5 (2) Apr 06, 2015
Don't forget this is the first iteration right out of the labs. They will be improved, no doubt. The only caveat I have is if the Lion battery takes say 90 minutes to charge and this one with the same amp hour rating takes 1 minute, you are going to have to stuff 90 times the charging rate to get it to charge that fast. So if the Lion battery has say 9 amp hour rating which takes say 9 hours at one amp, then the new battery to charge in one minute would require 540 amps to charge the same energy in one minute. Of course it is still stuffing 9 amp hours into the battery but you see the point, the faster the charge, the more current you have to use to get to the same level of charge. So a 2000 ma hour battery, 2 amp hours, if it charges in 90 minutes would require about 25 ma charge current for 90 minutes. So now you need to stuff 2 000 ma or 2 amps into the battery to get it to full charge in 1 minute. Not impossible but it means a much higher energy charging system.
betterexists
2.3 / 5 (3) Apr 06, 2015
What is Tesla's take on this? Aluminum Body, Aluminum Battery, WoW.
1 Million of them per car should suffice!
Nobuo
3.7 / 5 (3) Apr 06, 2015
No energy density / specific energy data, that is the most important info we need to compare with other solutions
Bongstar420
1 / 5 (1) Apr 06, 2015
This is graphene technology...Aluminum is a dopant.
TheEyeofTheBeholder
1 / 5 (2) Apr 06, 2015
Now, if we can get America to stop throwing out cans, would be a start...home depot does not recycle but cardboard... So sad...
Dethe
2.5 / 5 (2) Apr 06, 2015
This is graphene technology...Aluminum is a dopant
Why do you think so? The aluminium doesn't form intercalates with graphite with compare to lithium.. The aluminium atoms are large, they don't fit between graphene layers.
zerobokeh
Apr 06, 2015
This comment has been removed by a moderator.
MR166
5 / 5 (4) Apr 06, 2015
"We need a battery that once charged will power, say a smart phone, for a week of continuous use."

Wow we are getting more ignorant by the minute!!!! Out of all the possible uses for a cheap battery that can be recharged 10K times a cell phone is offered as the most pressing need.
betterexists
1.5 / 5 (4) Apr 06, 2015
@MR 166
WHO IS IGNORANT?
In these Wireless charger days, just hangup your pants in the closet; The Cellphone inside your pants' pocket will get charged in a minute by the time you return from B'Room in a Minute after #1 VISIT! If you do not believe that Follow up with Visit #2
big_hairy_jimbo
2.8 / 5 (5) Apr 07, 2015
Just thought I'd mention The International Union of Pure and Applied Chemistry (IUPAC) officially standardised on the name "aluminium" in 1990. The other spelling is considered for laymen, though the discoverer of Aluminium did call it Aluminum at one point, then changed it.
ThanderMAX
5 / 5 (2) Apr 07, 2015
If they want to match 3.7V DC, they could series join two 2V DC Aluminium ion battery.

Also the new battery is thin, so series connection would not make a huge difference IMHO
antialias_physorg
5 / 5 (4) Apr 07, 2015
No energy density / specific energy data, that is the most important info we need to compare with other solutions

Follow the bouncing baby link at the bottom of the article. The numbers are right there.
Nerdboy207
1.5 / 5 (2) Apr 07, 2015
@zerobokeh Why Chinese spies in Stanford university. I think it's spies based out of the Epsilon Program religion spying on us in an attempt to rule the world. Kifflom
casualjoe
not rated yet Apr 07, 2015
This is graphene technology...Aluminum is a dopant
Why do you think so? The aluminium doesn't form intercalates with graphite with compare to lithium.. The aluminium atoms are large, they don't fit between graphene layers.


It's not just the size of the ions that determines whether they fit between the layers, it is also the ionisation energy. In this case, they are intercalating the graphite with AlCl4 when charging.

This looks promising for home energy storage so I've started experimenting on this idea myself and if I get any good results I want to just share them with everybody for free.
Eikka
5 / 5 (6) Apr 07, 2015
Now that the DOI link works, we can see that it has a specific energy density of around 140 Wh/kg which is comparable to early lithium-ion batteries.

In comparison, a Tesla 85 kWh battery pack has approximately 150 Wh/kg including all the supporting structures, which amount to about a third of the mass. The plain cells should come in at around 230-250 Wh/kg.

This is the reason why it's important to get the cell voltage up - the higher the voltage, the higher the specific energy density. As it stands though, the invention has important implications for other automotive applications, like car starter batteries because the very high discharge rate and long cycle life may directly replace lead-acid batteries. Even the 2 V cell voltage is a direct drop-in replacement, because car batteries are 6x 2 V cells in series.

MR166
5 / 5 (2) Apr 07, 2015
Also if the battery is as resistant to catastrophic as claimed the cooling and packaging weights could be lowered substantially.
michael_f_ellis
5 / 5 (2) Apr 07, 2015
I don't have access to the full text of the Nature article. Does anyone know what the dod ( depth-of-discharge) was for the 7500 cycle lifetime? Industrial deep-cycle lead-acid batteries are typically spec'd at 1000 cycles at 50% dod. If the technology reported here can do 50% or better for 7500 cycles and has a reasonably low self-discharge rate, it starts looking very good for utility-scale applications to buffer PV and wind generation.

A little Googling indicates that Al and graphite are each available in bulk for under $2/kg. Assuming a $10/kg sales price (charger included) and the reported energy density of 140 wh-kg, the rough life-cycle cost per kwh stored and retrieved at 50% dod would be

$10/(0.14*.5*7500) = 1.9c/kwh

If the battery can do 80% dod, the cost comes down to 1.2c/kwh.
multilis
2 / 5 (1) Apr 07, 2015
7000 cycles... you can't fully test that in lab in short period of time. Eg battery in real world could fail in matter of months from other factors.

Lithium batteries, often get 80%+ energy out of them compared to putting in, some aluminium techs you put in several times as much energy to charge them/recycle as get out after.... not so important for cell phone but important for car/stationary.

weight... important for cell phone, probably 2x+ as much weight.
betterexists
1 / 5 (3) Apr 07, 2015
It is a big shame that each house does not have its own power with a battery capturing energy from sun for the nights too....A big shame to endure power outages....!
Probably, so many things can be done differently but for the Greedy Corporations.
Corporations may be doing good but certainly could do better. One Example I can give is Hoarding of Funds in Swiss Banks without using that for ESC Research, Infrastructure Whatever.
Another Example I can give is pouring money into religion related activities in this Modern era of Science & Technology.
One More Example I can give is letting Carnivores Prey on Herbivores which could be utilized for humans...food, fish (vs. crocs), biofuel....What Not!
To tell the truth, Why Dinosaur sized Whales Too!
We could have gotten double the amount of fish....So, at 1/4 the current price on the dinner table!
betterexists
5 / 5 (1) Apr 07, 2015
It is a big shame that each house does not have its own power with a battery capturing energy from sun for the nights too......A big shame to endure power outages....!
READ: "New report identifies possible next steps in US energy development" ; "In the U.S. we don't really understand much about energy: where it comes from, the scale of demand or the benefits and challenges of producing different kinds of energy." said Scott Tinker, Director of the Bureau of Economy Geology at the University of Texas at Austin, and State Geologist of Texas, "I don't know where things will stand 50 years from now, but I do know that, like today, we are still going to be looking for sources that are affordable, accessible, reliable and sustainable. Those tenets will drive the energy mix, whatever it turns out to be."
multilis
5 / 5 (1) Apr 07, 2015
(We have had claims of supercapacitors that could handle 2000+ volts rather than just 3 volts for years which in own way would accomplish similar... and many years later none in market.

We have had claims of lead/carbon batteries for many years as breakthrough and yet not in market)
MR166
1 / 5 (1) Apr 07, 2015
"Probably, so many things can be done differently but for the Greedy Corporations."

Good god people you do not have even the slightest idea of what is possible on a cost effective basis. You think that any product that you can imagine would be affordable but for greed.
Eikka
4 / 5 (3) Apr 08, 2015
7000 cycles... you can't fully test that in lab in short period of time. Eg battery in real world could fail in matter of months from other factors.


Why not? Two minutes per cycle takes only 10 days.

Does anyone know what the dod ( depth-of-discharge) was for the 7500 cycle lifetime?


It appears they ran it down all the way to 0 V, so 100% DoD.

Also if the battery is as resistant to catastrophic as claimed the cooling and packaging weights could be lowered substantially.


The current lithium-ion batteries aren't shielded properly to start with. Tesla had to add more armor to the bottom of the car, and they don't count that towards the weight of the battery pack because it's structural to the car's chassis.
MR166
4 / 5 (2) Apr 08, 2015
"It appears they ran it down all the way to 0 V, so 100% DoD."

Well most batteries loose a lot of life expectancy when discharged 100% so this was really an extreme test. Good for them, I really hope that this is the breakthrough that we all have been looking for.
Eikka
5 / 5 (2) Apr 08, 2015
Well most batteries loose a lot of life expectancy when discharged 100% so this was really an extreme test.


Maybe it needs to be discharged completely. They're basically electroplating a graphite electrode with aluminium, and if it's not completely cleared with each discharge and the aluminium returned back to solution, maybe it starts to form lumps and dendrites.

It's too early to say before they put it through the mill and see what comes out.

The discharge curve has an interesting double plateau, first above 2 V and the second at 1.7 V at about 80% DoD indicating that there's two kinds of reactions going on. First something gets deposited, and then something else gets deposited on top of that, and each has a different treshold voltage.
casualjoe
not rated yet Apr 08, 2015
The paper is here if you would like to take a look.. https://www.dropb...ocx?dl=0

Not sure if I'm allowed to do this, oh well.
starpigeon
1 / 5 (1) Apr 09, 2015
Actually it is only a new kind of supercapacitor, even though they claimed that it was an aluminum ion battery. It is the ionic liquid electrolyte (EMImAlCl4) that reacts with (AlCl4- anions intercalate into) graphite foil under moderate voltage, not Al3+ cations from Al electrode. If the Al electrode is replaced by other stable metal or graphite, the results should be the same. Compared with other real aluminum ion battery (Chem. Commun., 2011, 47, 12610–12612), its specific capacity is too low (60 vs 273 mAh/g). As a supercapacitor, its specific capacitance is only 4A/g*54s/(2.45-0.4V)=105.4 F/g. I can only smile on this "Nature" paper.
Eikka
5 / 5 (2) Apr 11, 2015
Actually it is only a new kind of supercapacitor


It doesn't behave like a capacitor.

If it was acting as a capacitor, the voltage would depend on the collected charge instead of the electrochemical potential of the electrode materials, and there would be no voltage plateau in charging or discharging.

starpigeon
3 / 5 (1) Apr 11, 2015
Actually it is only a new kind of supercapacitor


It doesn't behave like a capacitor.

If it was acting as a capacitor, the voltage would depend on the collected charge instead of the electrochemical potential of the electrode materials, and there would be no voltage plateau in charging or discharging.



What you said is mainly based on Electrical double-layer capacitors (EDLC), not pseudocapacitors.Electrochemical pseudocapacitors use metal oxide or conducting polymer electrodes with a high amount of electrochemical pseudocapacitance. Pseudocapacitance achieved by Faradaic electron charge-transfer with redox reactions, intercalation or electrosorption. (from Wikipedia) You can always find voltage plateaus in charging and discharging. Please check papers J. Mater. Chem. A, 2014, 2, 3223-3230 or doi:10.1038/srep01470.
N6FB
4 / 5 (2) Apr 11, 2015
Apparently this battery will support high discharge rates, based on the charge rate data. Now if only the energy density is at least twice that of the lith-ion technology, we are really on to something for electric cars that have enough range to make them truly feasible for general use.

I hope we get there before we get asymptotic to the laws of chem and physics.

Eikka
5 / 5 (2) Apr 12, 2015
What you said is mainly based on Electrical double-layer capacitors (EDLC), not pseudocapacitors.


Well...

As a supercapacitor, its specific capacitance is only 4A/g*54s/(2.45-0.4V)=105.4 F/g. I can only smile on this "Nature" paper.


E=½CV^2

That's still 58 Wh/kg at 2 Volts, which is equivalent to NiCD/NiMH batteries. If it was a supercapacitor, it would be a world record with 4-5 times greater energy density than preceding attempts. Clearly the claim that it's "only a capacitor" doesn't pass the straight face test.

The numbers sound too incredible, so I think you're mistaken.
starpigeon
3 / 5 (1) Apr 12, 2015
E=½CV^2


Come on, buddy! you cannot judge the type of energy storage devices by calculating the energy density. It makes no sense. The mechanism functioning inside the devices determines the type. In conventional batteries, ions (Li+, Na+ and Mg2+, et al) continuously migrate from one electrode to another through electrolytes during charging-discharging cycles while the electrolytes remain stable. In supercapacitors, the ions from the electrolytes (not dissolve from counter electrode) insert into active materials or are adsorbed on the surface, and the electrolyte is polarized. With regard to this paper, the AlCl3 (or AlCl4- cations) from AlCl3/[EMIm]Cl electrolyte intercalated into graphite. The counter Al electrode can not compensate the AlCl3 or AlCl4- ions consumed during charging.
So I have to say the device is more a two-electrode supercapacitor than a real Aluminium-ion battery.
casualjoe
5 / 5 (1) Apr 12, 2015
As a supercapacitor, its specific capacitance is only 4A/g*54s/(2.45-0.4V)=105.4 F/g. I can only smile on this "Nature" paper.


You can't simply use the specific capacity equation to derive the specific capacitance. What if the voltage window was (2.45-2V)? You'd then get 480 F/g...!

I think you're right though, it seems like there are extrinsic pseudocapacitive effects happening where the anion goes into the graphite, allowing fast charging and the like.

I'd like to make up an iodoaluminate ionic liquid and try that as the electrolyte to increase the voltage. But for now it's a case of focussed study on the growth of these crystalline graphite structures with the overarching aim to build them cheap and (relatively) easily.
casualjoe
not rated yet Apr 12, 2015
The counter Al electrode can not compensate the AlCl3 or AlCl4- ions consumed during charging.
So I have to say the device is more a two-electrode supercapacitor than a real Aluminium-ion battery.


It takes 7AlCl4- ions to 1Al atom to release the electrons, so it seems like galvanic oxidation only has to compensate at 1/7th the speed of intercalation, (don't quote me on that, ha) but it is still probably a limiting/contributing factor during charge/discharge.
starpigeon
not rated yet Apr 12, 2015
It takes 7AlCl4- ions to 1Al atom to release the electrons

we need to analyze what happened to the anode and cathode during the charge and subsequent discharge process.
Charge:
Al electrode: 4Al2Cl7(-) +3e(-)--Al+7AlCl4(-) (new Al deposited onto Al electrode from electrolyte)
Graphite electrode: Cn+AlCl4(-)--Cn[AlCl4(-)]+e(-)
Discharge:
Al electrode: Al+ 7AlCl4(-)--4Al2Cl7(-) +3e(-) (Al deposited in charge process dissolved!)
Graphite electrode : Cn[AlCl4(-)]+e(-)-- Cn+AlCl4(-)

No Al atoms from Al electrode really participate in the reaction. It is the electrolyte that reacts with graphite, not Al atoms from Al electrode. So you can replace the Al electrode with other metal or graphite, under moderate voltage, you can get the similar electrochemical performance. Then, what kind of device are you making?
betterexists
not rated yet Apr 12, 2015
3 to 4 Good news reports on batteries recently; 1 by Google X , 1 by S. Carolina, Another one is this current one. New material could boost batteries' power, help power plants. A team of researchers, including Kyle Brinkman of Clemson University, developed a material that acts as a superhighway for ions. Ye Lin, Shumin Fang and Fanglin Chen, all of the University of South Carolina, collaborated with Brinkman and Dong Su, who is with the Center for Functional Nanomaterials at Brookhaven National Laboratory in Upton, New York.
Eikka
5 / 5 (1) Apr 14, 2015
Come on, buddy! you cannot judge the type of energy storage devices by calculating the energy density. It makes no sense.


Why?

If you say it's a supercapacitor, wouldn't it ought to act like one and have energy densities at least similiar to other supercapacitors?

Unless you claim they've actually found a super-super capacitor.

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