Nickel Iron Battery Electrolyte?

[backwoodsmun]

I have some nickel-iron batteries that will eventually need to have the electrolyte renewed.  Despite a lot of web searching, all I've found is history lessons and such concerning these batteries.  Is there a USA industrial chemical supplier of reaonable cost for the ingredients and what else goes in besides KOH?

I also have some small wet-cell NiCd batteries that would benefit from renewed electrolyte.  Will the same electrolyte serve?

[thunderhead]

You can buy the electrolyte for nickel iron batteries from caving shops.  It is the same as that used for NiCd: normally potassium hydroxide with some lithium hydroxide.

Here is an example from the country where I live.

http://www.caving-supplies.co.uk/cgi-bin/psProdDet.cgi/31034||~@c~KOH~@b|0|user|1,0,0,1|1

I'm sure you can find it closer, though.

[twidget]

I also have a set of flooded nicad bateries that I am thinking could stand  to have the electolyte changed in them. I have done a deal of searching for replacement electrolyte, but have come up empty  handed. There are some good articles in the Home Power Magazine archives on making your own electroyte, but the source for the chemicals is the sticking point. If anyone knows of a source for the Nicad Electrolyte, I would also like to know where.

Just my 2 cents

Twidget

[MelTx]

  I think that potassium hydroxide is the main body of common household drain cleaner such as Red Devil.It is also called potash,makes a good hand cleaner,cleans your flesh right down to the bone.Also has strong reactions when water is added.So rubber gloves and glasses are in order.

[stop4stuff]

I found this page the other day, loads of places & common products that contain various chemicals... potassium hydroxide is about 3/5 of the way down the page.

http://www.hyperdeath.co.uk/chemicals/inorganic.html

MelTx - Red Devil (lye or caustic soda) is sodium hydroxide

[Nando]

USE pure KOH = potassium hydroxide 30 %

DO NOT USE WITH Lithium

Nando

[backwoodsmun]

Thanks Nando. I've seen the electrolyte described as 30% KOH with a little LiOH, though never a definition of "a little".  When you say no lithium, do you mean not even as an additive, or don't use LiOH instead of KOH?  The significance of LiOH as an additive is never made clear.

Thanks to other folks for the various inputs concerning products containing caustics, but something apparently important I've seen in the search is the need for "battery grade" chemicals.  Evidently, non-graded chemicals may contain significant impurities that can cause problems in the battery, especially other metals.  Battery grade is less pure than laboratory grade (and much cheaper), but better than industrial grade.  This is just what I've found ... I don't know how much an issue it might be.

I don't know about other places, but where I live pretty much all the household products containing caustic use sodium hydroxide (cautic soda), rather than potassium.  But I'd think any household product might be too impure to safely use in a battery. Maybe it would reduce capacity or shorten lifespan or such.  But I'm just speculating here. I have NO experience in this area.

[thunderhead]

The lithium hydroxide apparently increases the life of the nickel electrode.  Since the chemistry of the nickel electrode is the same in NiCd and NiFe, this suggests that a NiFe battery should include lithium hydroxide.

http://www.cadmium.org/app_batt.html

From memory, I think it's mentioned in Edison's original patent.

[Nando]

HECK I THOUGHT I WAS PERFECT BUT I MADE A MISTAKE - one of several hundred dozens today.

Yes LITHIUM will be good for the battery to prolong the Nickel life.

Nando

[shay]

Cells just arrived. Included was KOH (58.6 Kg) and LiOH (4.1 Kg).

[shay]

Always use safety goggles and gloves. Have copious amounts of water available in case of accident. Vinegar neutralizes. Add KOH/ LiOH to water (water added to powdered alkali/ concentrated alkali solution, can spatter/maybe explode). Measure SG when it has cooled.