Has anyone looked at zinc-air fuel cells lately?

[TheWraith]

I'm particularly interested in the models listed by PowerZinc.com. 41 kilowatt-hours on a load is nothing to sneeze at. Of course I'll probably find out that they cost $20,000 or something.

[PoiBoy]

1. Thanks for the link...

I find these technologies amazing and innovative...

:hi:

[TheWraith]

2. It's one of the few current fuel-cell technologies that's really in mass production.

There's hydrogen of course, but storage and refueling is more difficult. But the zinc-air systems seem cool. That 94/94-440 model, if their specs are right for amp-hours and voltage, could drive a reasonably efficient electric car 200-250 miles on a single "tank" of zinc. Plus the resulting zinc-oxide can be reprocessed via electrolysis to produce fresh zinc!

[madokie]

9. I can see very few downsides to it

unlike a battery this is a fuel cell, a whole different animal, am I not correct?

[kristopher]

3. 52% energy storage efficiency?

Yes, people have looked at it.

[TheWraith]

4. I'm sorry, was there information amongst that snark?

:eyes:

[kristopher]

5. No snark.

You asked a question and I answered. The limitation of the technology is storage efficiency that is approximately 1/2 that of lithium while offering little advantage elsewhere.

What this means in practical terms is related to the question of "what are we going to do with it?" If we are going to build a renewable energy infrastructure around this technology then you have take into account that with such an efficiency rating you'll require double the energy generating infrastructure to power your society. Instead of feeding your EV 52kwh of electricity, you'll have to feed it 104kwh to get 52 kwh of use. In order to feed it 104 kwh of electricity you'll have to have more generation.

Simple really.

[TheWraith]

6. Actually, it does offer a substantial advantage, in that it's quickly and easily refuelable.

Also that unlike, say, hydrogen, if abused the fuel isn't likely to... what's that word... explode. Not saying they're ideal, but they do have the advantage of being actually available, unlike most of the technologies that get talked about here.

And if we're going to build a green energy grid we're going to have to build it well enough that an added 52 KWH doesn't make a big difference.

[kristopher]

8. I've never endorsed H.

It is dead for the same reason, low system efficiency. The Zinc air battery is around 52% STORAGE efficiency while a H fuel cell is at around 60% SYSTEM efficiency. I'd be willing to bet the SYSTEM efficiency of the Z/A sucks.

[TheWraith]

10. I'd love a pure-battery system too, but until/unless we perfect fast-recharge Li Ion

There's going to be a market for long-range vehicles powered by something else. I'd rather have a fuel cell than ICE, but we'll see what shakes out.

[madokie]

11. Isn't the fuel cell a whole different animal as to a battery as such?

If I understand this right there is no recharging this cell by pumping electricity into it, am I not correct?

[kristopher]

7. We know one thing about the company - they lie

The first thing you see on their home page is a string of mistatements:
Existing batteries for EV are facing the following major problems:
Insufficient energy density that severely limits the range of the vehicles:
typically only 30 to 50 km per recharge ;

Long recharging time: usually 8 hours;

Short Service Life: typically less than 2 years;

High unit cost of other advanced technologies, such as NiMH or Li-ion;

Unstable performance of other advanced battery technologies, such as potential explosion disaster of Li-ion

Secondary Pollution, such as Lead-acid battery.


It's my experience that a company that has to lie about their opposition, probably has an inferior product. Add to that the fact that ALL manufacturers have selected lithium as the preferred platform and you have a quick picture of a technology with a fundamental flaw. My guess is that the problem is the one I noted earlier, low efficiency. IF you check their list above against the product performance claims by EBox, Lightening, Tesla you'll see a substantial difference.

[madokie]

12. Zinc-air batteries (non-rechargeable),

http://en.wikipedia.org/wiki/Zinc-air_battery

and zinc-air fuel cells, (mechanically-rechargeable) are electro-chemical batteries powered by the oxidation of zinc with oxygen from the air. These batteries have high energy densities and are relatively inexpensive to produce. They are used in hearing aids and in experimental electric vehicles. They may be an important part of a future zinc economy.

Particles of zinc are mixed with an electrolyte (usually potassium hydroxide solution); water and oxygen from the air react at the cathode and form hydroxyls which migrate into the zinc paste and form zincate (Zn(OH)42-), at which point electrons are released and travel to the cathode. The zincate decays into zinc oxide and water is released back into the system. The water and hydroxyls from the anode are recycled at the cathode, so the water serves only as a catalyst. The reactions produce a maximum voltage level of 1.65 volts, but this is reduced to 1.4–1.35 V by reducing air flow into the cell; this is usually done for hearing aid batteries to reduce the rate of water drying out.

The term zinc-air fuel cell usually refers to a zinc-air battery in which zinc fuel is replenished and zinc oxide waste is removed continuously. This is accomplished by pushing zinc electrolyte paste or pellets into an anode chamber. Waste zinc oxide is pumped into a waste tank or bladder inside the fuel tank, and fresh zinc paste or pellets are taken from the fuel tank. The zinc oxide waste is pumped out at a refuelling station and sent to a recycling plant. Alternatively, this term may refer to an electro-chemical system in which zinc is used as a co-reactant to assist the reformation of hydrocarbon fuels on an anode of a fuel cell.

Zinc-air batteries have properties of fuel cells as well as batteries: the zinc is the fuel, the rate of the reaction can be controlled by controlling the air flow, and used zinc/electrolyte paste can be removed from the cell and replaced with fresh paste. Research is being conducted in powering electric vehicles with zinc-air batteries.

[NNadir]

13. Yeah, I have a couple of papers on them in my files. I'll dig 'em up when I head home from my

business trip if I think of it.

There was an interesting one involving the Boudouard reaction, not exactly the same cell, but one with interesting properties in the synthesis of carbon monoxide from carbon dioxide. It was a neato molten salt thingy.