Homebrewed Electricity > Storage
So I went down the Nickel-Iron battery rabbit hole...
SimonMester:
Yeah it is nasty stuff. I studied biochemical engineering, and only ever used small amount of acids and bases, and always very slowly.
I have deep respect for it. Exothermic reactions are no joke.
Not going to mix any of the stuff without an ice bath that's for sure.
SimonMester:
So after digging even deeper, this is the one chemical route I found so far, on affixing the oxides (iron and nickel) to the electrodes:
"Iron (anode) Plate
To make the iron anode, first mix 6 1/4 grams of iron oxide with 1 1/4 gram of ammonium chloride,
then add distilled water a drop at a time until a stiff
paste results. The mixture will give off ammonia gas and will turn to a
white color. Working quickly, smear the paste well into a 1½ x 6-inch piece
of No. 20 or 30 close mesh iron or copper wire screening.
It will take about a day for the paste to thoroughly set and harden on the
screen, or you can hasten it by placing it in an oven set at no more than
130°F. When dry, lay screen in a solution of ammonium chloride (12½ grams to
6 oz. of water), for about 1½ hours to harden it further. This completes the
anode plate.
Nickel (cathode) Plate
To make the nickel cathode, first mix 6 1/4 grams of nickel oxide with 1 1/4 gram of ammonium chloride,
then add distilled water a drop at a time until a
stiff paste results. The mixture will give off ammonia gas. Form this plate
directly on the surface of a 1½ x 6-inch. piece of .015 inch or thicker
nickel screen, which has been cleaned thoroughly with emery cloth. Working
quickly, smear this paste well into a 1½ x 6-inch piece of No. 20 or 30
close-mesh nickel wire screening.
It will take about a day for this paste to thoroughly set and harden on the
screen, or you can hasten it by placing it in an oven set at no more than
130°F. When dry, lay screen in a solution of ammonium chloride (12½ grams to 6 oz. of water),
for about 1½ hours to harden it further.
Fill a wide mouthed jar or a 1000 ml. Beaker with 32 oz. of distilled water.
Dissolve 9¼ grams of sodium hydroxide (lye) in this water and add 1 gram of
common table salt. Sodium hydroxide is hard on the hands and clothes in its concentrated form,
so don't handle the crystals with your fingers and always add the crystals to the water slowly.
Mark the iron oxide plate negative and nickel oxide positive now to avoid
mistakes. Connect a battery charger or car storage battery to the plates,
negative to iron oxide plate and positive to the nickel oxide plate, also a
direct current ammeter or digital multi-meter and a l0-ohm 25-watt resister
is added in series with the forming current. Turn on the forming current and
adjust the variable resister so that only 1 ampere of forming current flows.
It is important that you observe polarity right at the first charge.
Connecting the negative lead to the iron oxide plate and the positive lead
to the nickel oxide plate. This charge must be (2 or 3 hours), because the
iron oxide plate must be converted to metallic iron. It doesn't matter if
the plates gas in this forming charge.
Attach the cathode and anode plates to a strip of wood to test them. Fill
another 13-oz. glass tumbler with about 9 oz. of distilled water and slowly
dissolve 3 oz. of sodium hydroxide in this to form the electrolyte of the
iron-nickel cell. Suspend the plates in this liquid. Now your cell is
complete. Cell voltage on open circuit will be right around 0.75 volts for
this iron-nickel Edison cell. "
Since I have very little clue on why and how ammonium chloride would work with this cell, or what it would be doing while the battery is in operation, I'm quite cautious of just taking this random conversation at face value.
Anyone with a higher degree of understanding of chemistry, care to pitch in?
PPE and hazards aside, I mean purely for how and why this could function.
I also note he specifies for the meshes to be Nickel on one side and Iron on the other. This confused me a little, as it is the Iron and Nickel oxides doing the work as far as I understood before. The meshes are supposed to just be corrosion resistant current collectors, thus usually being nickel plated steel? Not sure about that part in the conversation either.
If this was a workable solution however, that would make producing such a cell quite viable, at least for experimentation purposes at first.
I'd rather use a chemical paste like that, than some silver doped epoxy that costs an arm and a leg.
Anyways, any input welcome! It's surprisingly hard to find answers for this chemistry via just googling.
SimonMester:
So I have further looked into the few sources on the subject. Lots of old patents and projects. I have compiled the most successful ones, and will try reproducing them. I'll have a bias for the more simple designs, naturally some of those century old patents are not only large scale, but super complex manufacturing too.
I'll post my updates here and on youtube as I go along.
It will be a slow process I imagine, due to the lack of funds, so I started a mini crowdfunder, in case anyone is interested in pitching in, I appreciate it for great science!
(https://gofund.me/b516f7b4)
I have found a source of small 100ml polypropylene jars, and dense stainless steel meshes.
The first and one of the most complex challenges will be figuring out the electrodes. I am going with forming various pastes of the oxides and drying them onto the meshes. The meshes will first need to be electroplated with Nickel.
Once I have succeeded there, I can move on to the electrolyte and run experiments with additives into that, for which I have several candidates, mostly inorganics.
Interestingly, for the electrodes, there are some organic acids that are mentioned, so once I have some cells running with an established performance, I'd love to manufacture electrodes with different additives and run long term comparisons.
MattM:
I don't play with ammonia myself. Nasty stuff. Use extreme caution and dope it with a tracer so you smell leaks.
SimonMester:
--- Quote from: MattM on December 12, 2023, 06:46:40 PM ---I don't play with ammonia myself. Nasty stuff. Use extreme caution and dope it with a tracer so you smell leaks.
--- End quote ---
Yes, I am not thrilled about making ammonia gas. I am ascertaining the danger. A small amount is released, in an outdoor setting, with full face respirator. I'm trying to math out as well as ask around to see if that gets dispersed reasonably so as not to pose a problem, as I have not worked with ammonia, I want to be sure.
Gases terrify me more than the strongest of acids tbh.
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