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Stanford team develops ultra-fast aluminum-ion battery with stability over thousands of cycles

A team at Stanford University, led by professor Hongjie Dai, has developed a high-performance, safe, fast-charging aluminum-ion battery that can last for thousands of cycles. The Al-ion battery—comprising an aluminum anode, graphite cathode and ionic liquid electrolyte—produces about half the voltage of a Li-ion battery. In addition to powering small electronic devices, Al-ion batteries could be used to store renewable energy on the electrical grid, Dai said.

A paper describing the novel aluminum-ion battery will be published in the journal Nature.

We have developed a rechargeable aluminum battery 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. Our new battery won’t catch fire, even if you drill through it.

—Prof. Dai

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.

Aluminum batteries developed at other laboratories usually died after just 100 charge-discharge cycles. In contrast, the Stanford battery was able to withstand more than 7,500 cycles without any loss of capacity. Another feature of the aluminum battery is flexibility, said Stanford graduate student Ming Gong, co-lead author.

However, more improvements will be needed to match the voltage of lithium-ion batteries, Dai said.

Our battery produces about half the voltage of a typical lithium battery. 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.

—Prof. Dai

Other co-lead authors of the study affiliated with Stanford are visiting scientists Meng-Chang Lin from the Taiwan Industrial Technology Research Institute, Bingan Lu from Hunan University, and postdoctoral scholar Yingpeng Wu. Other authors are Di-Yan Wang, Mingyun Guan, Michael Angell, Changxin Chen and Jiang Yang from Stanford; and Bing-Joe Hwang from National Taiwan Normal University.

Resources

  • “An ultrafast rechargeable aluminum-ion battery,” Nature

Comments

HarveyD

Light weight aluminum is available at much lower cost than lithium.

At over 7000 cycles, this type of battery could last 20+ years or the fully life of future BEVs, even if recharged daily.

Being very light and flexible, those batteries could be integrated into car floor, doors, roof, hood and booth etc without reducing passenger essential space.

Lad

This is the same material that JCESR is working with. Al and Mg. I wonder how they're doing...haven't heard a status report from them in months.

kelly

No mention of EV use, so perhaps a slower power release than Phinergy, yet then the 1 minute recharge does't 'fit'.

JRP3

"Being very light and flexible, those batteries could be integrated into car floor, doors, roof, hood and booth etc without reducing passenger essential space."

I don't care what any battery is made of, it will never be a good idea to put high voltage on the outside of a vehicle.

I notice how there is no mention of Wh/kg at all...

Engineer-Poet

I noticed the same thing, JRP.

If the battery goes 7500 cycles without any capacity loss, it's probably good for many times that.  Even if the energy density is low, this would be perfect for hybrid vehicles (if the temperature range is wide enough).  Even if charging has to be limited to 30C, this means a 4 kWh battery could accept 120 kW of power during braking.  It would probably be able to supply that much or more with ease.  This makes a Tesla-style electric powertrain with a small sustainer engine a strong contender.  Or heck, just a stop-start battery.  1/2 kWh @ 30 C is 15 kW of surge power, plenty of oomph to start and even launch assist.

Suppose you get 100 Wh/kg; a 4 kWh battery would be 40 kg, not at all unreasonable.  Consider how much engine weight you could get rid of by eliminating 100 kW of peak power output.  None of the GCC posts on the new Auris engine mention its weight, but I'm sure it's at least 100 kg.

electric-car-insider.com

JRP3> it will never be a good idea to put high voltage on the outside of a vehicle.

It's cool. Ming Gong said it was bendable and nonflammable. They demoed it in the video. :-P

peskanov

The paper mentions 40 wh/kg.
Too heavy for cars, would be acceptable for bikes (China electric motorcycles use lead-acid, 2 Kwh is OK for city driving).

As an EV hobbyist, I consider 40 wh/kg (if real in driving conditions) acceptable if the prices is lower than lithium and cycling is as good promised. A good temperature range is algo important.
However, does not seem a good technology for commercial EVs.

peskanov

(On the second paragraph I was referring to cars).

mahonj

@Peskanov - "acceptable for bikes" ?
2KwH would weigh 50Kg - a bit much for a bike (or scooter).

More likely useful for solar load shifting where 10KwH would weigh 250 Kg and would probably be enough to buffer a house overnight for 6-7 months / year.

Or grid load balancing - stationary apps anyway.

peskanov

mahonj,
common Chinese motorbikes use 60 kg of lead-acid. They work well and are immensely popular. 50-100 kg of batteries in an motorcycle is acceptable, most megascooters weight up to 200 kg.

Stationary batteries does not benefit from fast discharge/charge speed, it would difficult to compete with stationary lead-acid.

Another interesting use in the EV space would be trucks and trains. Both types of vehicle have used lead-acid with some success, so it's competitive. Fast charge would help there.
Example: you could ran a city truck with 1 ton battery of 40 kwh, stop for 1 hour of fast charging and drive the rest of the day.

Could be an interesting technology, especially it it's more recyclable than li-ion.

Brotherkenny4

Should be good for solar. I wonder what projected cost is. If it's under $100/kWh it's a no brainer for solar. Energy density doesn't matter for stationary except that the large size might mean more material for non-energy components, and thus more cost.

Davemart

peskanov said:

'Stationary batteries does not benefit from fast discharge/charge speed, it would difficult to compete with stationary lead-acid.'

Loads from both solar and wind can vary sharply in a second or so, with passing clouds and gusts.

If the battery can't charge or discharge quickly, they need buffering with capacitors.

That of course adds to the cost of lead acid setups.

peskanov

Davemart:
yes, for grid levelling I guess it could make sense.
When mahonj mentioned stationary, I just thought common stationary, wich usually have very low C ratings.

Davemart

@peskanov:
They used what they had at acceptable cost.
If they can have high C rate as well, it opens up different ways of doing things and less buffering.

Engineer-Poet

At 40 Wh/kg, 2 kWh is 50 kg.  If you allow operation at 60C charge/discharge rate, you still get 120 kW of power and have more than enough energy.

A 40 kW sustainer (1/2 Auris engine) plus 120 kW of surge capacity allows continuous 70+ MPH cruise on level ground.  I'd have to dig into numbers for CoD and such to guesstimate grade performance, but imagine the rest:  you could put an induction motor on each wheel and have AWD with complete traction and stability control.  0-20 would be traction-limited to perhaps 0.9 second, 0-60 would be on the order of 4.5-5 seconds.  You'd get all that and still be able to achieve 40-50 MPG.  A car with that would sell like crazy.

peskanov

Engineer-poet,
you can do something close to that with 50KG of LiPo today.
But life expentancy of the battery would be short, I think.

However, the same could happen in this new chemistry; we heard it can charge/discharge at 60C, but we don't know about aging when used that way.

sola

This sounds great for stationary storage. Since it looks like it has immense cycle life (7500 w/o degradation, so even 30-40K may be possible down to 80%), I don't think lead-acid will be competitive with this if the selling price is similar (which should be due to the inexpensive materials).

Maintenance is a huge part of the cost when running stationary storage and lead-acid requires a fair amount of maintenance/replacement compared to this (although it is way too early to tell that, so this based only on the cycle life).

sola

I concur with the hybrid-suitability too.

Based on the high rate capability, this should be an inexpensive replacement for Ni-Mh batteries in full-hybrids.

If this is cheap enough, all cars could become strong-hybrids pretty soon.

As Aha

one their graph shows 60mA/g ant ~2V, dunno why they say it's 40Wh/kg not 120...

peskanov

If anybody is interested, you can take a peek at the paper at the nature journal:
[url]http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14340.html[/url]
It seems to need just graphite, aluminium and clhoride...this thing is really intriguing.

However, I don't think it shows potential to be cheaper than lead-acid.
Energy density being similar, aluminium is more expensive.

The graphite foam is another "unknown" factor for cost. It's not raw graphite.

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