Nickel-Iron Battery/Sourcing

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Research pertaining to Nickle Iron Battery sourcing.

Sourcing Research

FusionBeads [1] 3"x3" 24 gauge nickel sheet is $3.25.
Metric: 76.2x76.2mm and 0.5mm thick. The density of nickel is 8.902 g/cm3. 2903.22 mm3 which is 2.90 cm3. Thus, each sheet weights 25.84g. 2000g (2kg required as above) is 77.38 sheets. $251.50 is the cost of 2kg of nickel. Actually, it can be gotten cheaper in these quantities, but this is an outside number.

We need to look into purchasing in bulk as it is far cheaper than this sheet. Those guys must be making generous profit to say the least.

Wikipedia indicates that the price of metallic nickel these days is about 13 USD a kilogram, but it has been in the fifties during certain price spikes, I could not find a historical record, or even the current commodity price anywhere.

There are several ways to make the nickel electrode and active material which require different raw materials. See electrode sections for details. To both produce the nickel oxyhydroxide or hydroxide either inside the electrode matrix or as a powder of good particle size and porosity, which is then mixed into a paste and pasted into (with a matrix electrode) or onto (with a metal plate electrode, needs other additives to the paste) the electrode, there are several established economical ways that involve different raw materials, all of which will have different prices and availabilities:

  • Use a metallic nickel which is then oxidized electrochemically in a suitable chemical bath
  • Use the oxyhydroxide or hydroxide powder, which can be purchased directly in purities adequate for battery use
  • Nickel oxide (NiO2 I think), which is then roasted in air to oxidize it to the oxyhydroxide
  • Nickel nitrate, sulfate, and potentially other salts can be melted, the electrode dipped in, and then the electrode dipped in hot sodium hydroxide solution to convert the nickel through a binary reaction to nickel hydroxide. This has to be repeated several times to load the electrode.
  • To produce nickel hydroxide powder from some other salts, the nickel salt is sprayed into a basin of sodium hydroxide.

As long as we have nickel compound of adequate purity it's just a matter of figuring out an economical production method, or using an existing one. Which material will be needed can be chosen on price, availability and the ease and economy of the associated manufacturing technique.

Nickel could be recovered from the waste stream too, but this might not end up saving any money.

Iron as an element or in the form of steel is cheap, but a look on indicates that it may cost substantially more in pure iron powder. We might want to make our own in the production phase, especially if a design which only uses a fraction of the iron as active material is chosen. The first problem is purification, in which the carbonyl process or other industrial processes might be useful in scaled down form, but this is where the contributions of a chemist would be particularly welcome as there is probably something which is more practical. Then it needs to be powdered either mechanically or through chemical or electrochemical processes, or some combination thereof.

Purification may not be badly needed. It would improve performance but how much so needs to be worked out so an informed decision can be made.

The Edison process for producing the iron powder was much like what references indicate is the current process used for producing the powder for pocket plate batteries [the battery handbook, 3rd edition]:

  • Dissolve "pure iron" (how pure, what impurities are problematic can be nailed down to a fair degree from the documents listed in the sticking points section).
  • The FeSO4 is then re-crystallized (are we talking fractional crystallization here to purify it?), dried, and roasted (815 to 915 deg. C) (in what atmosphere? Air probably) to Fe2O3.
  • The material is washed free of any remaining [iron] sulfate, dried, and partially reduced in hydrogen.
  • The resulting material (Fe3O4 and Fe) is partially oxidized, dried, ground, and blended. Small amounts of additives, are blended in to increase battery life, depassivate the iron electrode, reduce gas production, and improving conductivity. (See other reaction and additives sections for details on potential additives.)

There are other ways established ways:

Heating iron oxalate in a vacuum produces a mix of iron and iron oxide powder High purity iron powder like carbonyl powder

Price of Nickel and Iron

Nickel price is very roughly $23 per kg. Pretty good really. price $0.60 per kg for scrap steel, presumably pure iron would be in that range.

From the electrochemistry figures above for a 1 kWh unit, that would be $48 or so on metals. So 20 Wh per $ ($0.05 per Wh). Even the cheapest lead acid batteries are 7 Wh per $. In reality they are more like 5. So the good news it that materials cost should not sink the ship anyway, although I'm sure all the other costs for the perforated pocket, assembly etc. will add up plenty fast.

Commercial Ni-Fe Suppliers

See Also