# Zinc-Air Battery Could Hold 300% More Energy Than Lithium-Ion



## david85 (Nov 12, 2007)

Heard about zinc air 10 years ago. They did some tests of the battery and proved it to have great energy and power density, but were unable to overcome the recharging part of the equation. The versions I saw were technically primary batteries. One version was "recharged" by pumping the active ingredients into and out of the fuel cell along with the electrolite.

Second and more powerful version from a different company relied on battery swapping and an elaborate plan to recycle dead batteries on a massive scale.

Both ideas died rather quickly as I recall. What I'm not seeing here is how exactly they plan to "recharge" the cells.

Earliest EV I know of that was powered by zinc air was the "electrovair" or electric corvair built by GM back in the 60s.


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## Sunking (Aug 10, 2009)

Zinc Air are primary cells.


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## Coulomb (Apr 22, 2009)

Sunking said:


> Zinc Air are primary cells.


Usually, yes. But they are talking in the article about increasing the current ~100 cycle life (I assume by electrical recharging, but maybe they mean via liquid) to 2000+.

As usual, the facts are a little lacking.


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## PhantomPholly (Aug 20, 2008)

Almost sounds like their "solution" (pardon the pun) is a hybrid between a fuel cell and a battery, the only difference being that by reversing the process they can "recharge" both the electrolyte and the reactant substances.

Fuel cells have been shown to hold the energy density we need, but the requirement to decant the spent liquid and replace with fresh plus the expense of replacing the Platinum catalyst were too problematic.


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## _GonZo_ (Mar 23, 2009)

I just started to work now on the development of Zinc-Air Batteries and Aluminium-Air Batteries.

Of course now it is dificult to say that they are going to be the future batteries for EV and other aplications, but they look really promising.
I suggest that you have a close look to them.

The can be recharged electricaly like other tipes of batteries.

And they can be charged mechanicaly, this is in my point of view the best option for EV it can be done in minutes. Just stop your car in a refuelling station and change the fuel (aluminium or zinc)

The good thing is that they can be around 500Wh/Kg or more, that is around 3 times better than good Li-ion batteries, and around 5 times better than LiFe batteries.

Another very good point of this batteries is that they can be in a almost in a perfect recicling process, this means that the battaries never die:
The Exausted fuel (oxide of Zinc or Aluminium) is converted back agin in fuel.
The electrolite is as well recicled agian and again.
And air catodes are recicled to make new catodes. 
Very little material is discard after a battery overhaul: little harware, some impurities, may be some catalizators, and some water is lost during the discharging/charging proceses but it is been worked in order to minimizise this lost.

You casn find a big open soure of information about Zinc-Air batteries here: http://elbil.forum24.se/elbil-about844-100.html (very long reading)

I will try to post more detailed and interesting information about them in some weeks when I get more knoweledge about them. (As comented I just started with them...)


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## order99 (Sep 8, 2008)

So-I need to be sure i'm reading this right:

1) The Zinc-Air battery can be quick-charged by replacing the internal fluids within minutes, safely and easy?

2) The ZA battery can also be slow-charged through normal charging techniques?

If this is the case, where is the downside? Early adopters would be at no more a disadvantage charging than LA or LiPo, get better performance AND get to take advantage of possible Quick-charge infrastructures at a later date?

There must be a downside i'm not seeing...if my understanding is correct, then why were these batteries not adopted sooner?


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## PhantomPholly (Aug 20, 2008)

The down side is that they only exist in laboratories.

As for how safe the fluids are or what the actual production energy density will be, it is all "vapour-ware" at this point.


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## david85 (Nov 12, 2007)

The electrolyte that the older ones I saw used was KOH (potassium hydroxide) which is a decently corrosive chemical. Lithium batteries have no liquid electrolyte in them.

Something else I should add, is there are lithium batteries out there that are being marketed in a limited capacity (with the help of exxon no less) with energy density of 400 WH/Kg, so its pretty close already. If we want to compare experimental against experimental, then there are lithium batteries that are "claimed" to be 600 WH/kg.

I agree with Phantom. There are too many vaporware batteries out there to believe any of these claims until I can buy one of these batteries and have it in my own hands. Claims alone of capability are not enough.


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## _GonZo_ (Mar 23, 2009)

> Something else I should add, is there are lithium batteries out there that are being marketed in a limited capacity (with the help of exxon no less) with energy density of 400 WH/Kg, so its pretty close already. If we want to compare experimental against experimental, then there are lithium batteries that are "claimed" to be 600 WH/kg.


Hi David, were can I find info about those Lithium batteries?


About the Zinc or Alum Air cells I forgot to say a couple of things.

In theory they can be very cheap, but that is something to be seen...
As Phamton says they are only in laboratories for now. (but hope that will be in mine soon)
About safety they are very safe, I mean VERY SAFE, actually you can perforate them and they will not even start a fire or smoke, actually they will continue working (Obviously not perfectly).


Just to let you know, my work with them is going to be the development of manufacturing sistems for them, and optimization of the cells and manufacturing procces itself.
So I think I will be in a good position in order to let you know all how it goes and if they are as good as they say.


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## Coulomb (Apr 22, 2009)

david85 said:


> The electrolyte that the older ones I saw used was KOH (potassium hydroxide) which is a decently corrosive chemical.


Yes, almost as bad as sulphuric acid, found in millions of lead acid batteries for a hundred (?) years. I don't know if the newer ones need this electrolyte. Acids and bases are common electrolytes, of course, because of their good conductivity.



> Lithium batteries have no liquid electrolyte in them.


Err, the prismatic LiFePO4 cells (e.g. Thunder Sky) typically have some liquid, which some call electrolyte, and I've heard the term "lithium hexaflouride" used, but it's not clear to me whether this is actually active material, or just conducting heat to the case.


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## _GonZo_ (Mar 23, 2009)

> Lithium batteries have no liquid electrolyte in them.


Lithium bateries have liquid inside, the electrolite.

Li-Ion on hard case is liquid.
Lipoly cells in bag have gel.
Life cells is liquid.


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## david85 (Nov 12, 2007)

My understanding is that LiPo batteries use a synthetic solid electrolyte. Haven't looked at it in a while though, so I'll take your word for it that I am wrong. I don't have as much time for research anymore. Main point I was trying to make is there isn't a large amount of fluid sloshing around inside (which the pumping method of fuel cell would require, for example). There may be some liquid, but its not something that will cause a significant amount of spill in a failure situation.

Here are the experimental batteries that I mentioned earlier:

Lithium sulfur
http://www.sionpower.com/technology.html

Lithium "super polymer" (this is the one that exxon played a role in)
http://www.greencarcongress.com/2005/05/maya_100_ev_to_.html

Company website
http://www.electrovaya.com/Default.aspx

Looking at electrovaya's more recent website, they seem to be distancing themselves from the 400wh/kg target. I can't find if anywhere in the up to date documentation. Perhaps they were blowing smoke. I remember years ago they specifically stated the 400wh/kg was in the works but its gone now.

All the more reason projections on paper aren't worth much IMO.
If this works well, than I wish you good luck but I can't believe any claims until I see the proof.

Lithium sulfur is said to have a theoretical limit of over 2000 wh/kg. Sounds great but getting results seems to be a bigger challenge than stating numbers or making claims.


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## david85 (Nov 12, 2007)

Just to clarify, I was also wrong to say that a 400 wh/kg battery was being marketed. The one I was thinking of is in fact closer to 250.


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## major (Apr 4, 2008)

PhantomPholly said:


> The down side is that they only exist in laboratories.
> 
> As for how safe the fluids are or what the actual production energy density will be, it is all "vapour-ware" at this point.


Hi Phantom,

Look over http://www.electric-fuel.com/EV/index.shtml 

A guy I work with did a contract job about ten years ago making the can and subsystems for a zinc-air bicycle battery. I think it worked, but the developing company kind of disappeared. I remember them making a big deal about having to get all the carbon out of the air electrode. Which wasn't easy.

But the company I linked to had buses running on zinc-air for years. Not sure they still are. I think the technology is more than vapor-ware. Ready for prime time? Probably not.

Regards,

major


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## PhantomPholly (Aug 20, 2008)

major said:


> Hi Phantom,
> 
> Look over http://www.electric-fuel.com/EV/index.shtml
> 
> ...


I hear ya. Buses are by nature nearly a laboratory environment, with strictly controlled routes and daily inspections/maintenance. A small prototype run using buses is, in my mind, is simply "Laboratory Phase II" - but that is purely subjective. 

The acid test (pun intended) is whether they can make a profit. Sounds like they couldn't back then, maybe this new group will figure it out.


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## _GonZo_ (Mar 23, 2009)

I have to say that the people that have contacted me in order to start developing hardware sistems for metal-air cells, they are still on developing process.
Actually they are quite far away to start producing any tipe of cells.

At the beguing as per what they said they had running experimental cells over 500Wh/Kg.
Finally what they have is just calcualtions about wat they are supose to do, but they do not even have one of those experimental cells running.

So sorry for the smoke.

Any way this weeks I have been studing about them quite a lot (I think that now I know more about them than some people at that company )
And actually metal-air cells look very interesting, and I am almost sure they will become real soon for EVs


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## david85 (Nov 12, 2007)

_GonZo_ said:


> I have to say that the people that have contacted me in order to start developing hardware sistems for metal-air cells, they are still on developing process.
> Actually they are quite far away to start producing any tipe of cells.
> 
> At the beguing as per what they said they had running experimental cells over 500Wh/Kg.
> ...


I seem to remember reading about aluminum cells and lithium-air cells too. Hypothetically, they could have crazy high energy density but until they are made for real, who knows......

Thanks for clearing that up. We try to stay as accurate as possible here. I say *try*, because as you can see, I just made the same mistake with that lithium superpolymer battery.


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## PhantomPholly (Aug 20, 2008)

Don't give up hope - with new announcements almost every day, ONE of them will be real.


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## david85 (Nov 12, 2007)

PhantomPholly said:


> Don't give up hope - with new announcements almost every day, ONE of them will be real.


Agreed....


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