Sciencemadness Discussion Board

Molten salt NaCl battery

aeacfm - 12-8-2014 at 03:42

i was wondering how to design a molten NaCl battery!
I have muffle furnace to melt the NaCl , but need to know anode , cathode materials , wiring , or what ever

metalresearcher - 12-8-2014 at 08:34

Well, it is not that easy. NaCl melts at 801ºC and can be mixed with CaCl2 (as it happens in industry) to lower it to 650ºC. The temperature itself is not the issue in your furnace, but capturing the sodium. At that temperature it very easily reacts with virtually everything.

In commercial plants it is done with a Downs cell with a carbon anode to get the chlorine and an iron cathode in a closed vessel to capture the liquid sodium metal on top of the salt solution as it is lighter than the salt. That makes it difficult as the cathode has to be excluded from air.

Another way to make Na metal is electrolyzing NaOH which I have done on a small scale. But the molten lye is VERY DANGEROUS to handle !!

Here I have a description:

But there are others in this forum with more sophisticated and better equipment.

aeacfm - 1-9-2014 at 02:03

thank you for your response
I am quiet confused if your comment regarding electrolysis cell or you mean i need the sodium for the design of the molten salt cell.
i thought i can use carbon or platinum as cathode and another metal as anode , i am just not sure
thanks in advance

Zyklon-A - 1-9-2014 at 06:57

The anode should be carbon, the cathode can be any metal, such as iron, or better yet, stainless steel.
We already have boatloads of threads about this, read one of those.

violet sin - 1-9-2014 at 09:07

wiki: Older thermal batteries used calcium or magnesium anodes, with cathodes of calcium chromate or vanadium or tungsten oxides, but lithium-alloy anodes replaced these in the 1980s, with lithium-silicon alloys being favored over the older lithium-aluminium alloys. The corresponding cathode for use with the lithium-alloy anodes is mainly iron disulfide (pyrite) with cobalt disulfide being used for high-power applications.