I was just messing around and had two pieces of soldering wire just stuck in a small cup using just deionized water and baking soda as an electrolyte with no sulfuric acid or anything extra.
And discovered I could charge the solder wires like a very weak tiny battery.

I decided to investigate further and expand upon the concept.
Took a good lenigth of solder wire and coiled it around a large hot glue stick. cut to length. with a sheet of paper towel as a separator. folded in half and wrapped around to insulate it to prevent any chance of an accidental short.. then wrapped another coil of soldering wire around the paper towel.
Then just dipped it in the cup let it soak up for a minute.
Then I began charging it and discharging it repeatedly at a moderate rate. not too slow or too fast
it seems like the more I use it the stronger it gets. outputting just over 1 and a half amps if short circuited!
I discovered it also helps massively if I discharge it completely then charge it backwards fully. then repeat until I'm tired of doing it.
it improves the capacity and discharge rate. as well as improving the current it can take when charging.

How is it able to work with just baking soda as a weak basic/alkaline electrolyte?
It gives just about 1.5-2v when fully charged. Slightly improving over time as I use it more and more.

I imagine if I had just big plates with highly textured surfaces I could get an even better result.

After cycling it a few dozen times the electrodes have gotten very dark and the positive has a dark brownish appearance.
The negative electrode looks very dark grey with just the slightest tinge of brown to a few places.
I'm using just cheap 63 37 tin leaded solder.
Anyone have any idea why this works? its kind of interesting

 

You must have heard of lead-acid batteries.
What you have created is a tin-lead-alkaline battery.

 

Yeah but I thought this wouldn't work with such a weakly alkaline based electrolyte. but it seems like it works pretty well on a small scale.
The tin content is probably way too high to be optimal though. so i'm probably losing a lot of potential capacity. its probably rechargeable over a thousand times though
Also another question do the lead electrodes continue to darken more and more the more its used and formed to higher capacity?
How dark should I be aiming for? Should I keep going until they are as dark as they are going to get. then stop? or for a little while after they reach maximum darkening?
I really should get some deionized water to use. instead of distilled water. Would be even pure-er for using. possibly lower leakage current and self-discharge and stuff.
If I wanted a higher capacity battery how about this stuff? Would this stuff work a lot better?
I can use soldering wire to make battery tabs/terminals super easily also. but seems like this would be cheap and easy to make a small scale battery a lot more effectively.
https://www.amazon.com/Fishing-Sinkers-Weights-Accessories-Supplies/dp/B09WDWHK1X
picking the 0.6mm or 1mm option would be best for durability and still cheap. And it gives me 10 rolls! So I could make multiple cells and and even multiple parallel plates.

I'm guessing it would help to give the surfaces a quick sanding to remove surface crud and whatnot to get a good result?
also any way to figure what the potential/voltage of this should be? and charging voltage/maximum voltage range. ect. its clearly lower than one made with sulfuric acid. but im not sure how much..

 

its almost able to run a small DC motor now for 10+ minutes! wow its starting to improve at an accelerating rate!
Ive had to raise the charging current to keep up. 0.3A of current

 

Lead based batteries are a very mature technology, and there is a lot of information published about them, most of it is not recent. So the created battery is certainly interesting but more certainly not practical from either a cost consideration or from an energy per unit volume consideration.
In addition, as it uses some lead, some will claim it is a health hazard.

 

Not really any information about a lead-alkaline battery though.

I'm pretty sure the super high content of tin is limiting the capacity my battery can reach. due to less actual lead material. as well as very low surface area (Smooth soldering wire strips with basically no surface area or rough texture.)
I think if I had just some much longer lead strips wrapped into a roll I could create one with massively higher capacity easily!
This is basically equivalent to two small 2.2 inch long 1.5-inch wide strips just in a crude cylinder around each other. not a long flat strip coiled up around itself multiple times with a rough surface. So the surface area and internal resistance are pretty low. along with a much lower content of lead as well.

 

This is pretty interesting. It never occurred to me to try making a battery. I might do this as an experiment with the kids. Thanks for posting!

 

Ok now the water has gotten very "cloudy" with something grey-white or white-ish I'm not sure what. Any ideas?
The small layer of excess baking soda that was on the very bottom of the pill bottle has almost completely disappeared. with some larger white-ish particles mixed with it. it seems to have been consumed in some way. or transformed into something thats dissolvable?
Also in a few places there seems to be a noticable "white" stuff thats formed. Tiny particle of something is loosely adhering to the electrodes.
I think I may need to consider replenishing or exchanging the electrolyte. Can't see very far into it.

With a discharge cycle its just about 0.6v at 10 minutes and still going for a bit before running out of capacity.
As it gets lower in charge. the voltage starts fluctuating quite a lot! Jumping around several tens of millivolts!

When charging it seems to just stay around 2.4-2.45v and goes up slowly until after some time the voltage suddenly rises very rapidly to something higher. then it steadies off and rises VERY SLOWLY about 0.1v to 0.2v more

After this and replacing the electrolyte several times to "refresh" it since it somehow loses conductivity. I tried replacing the electrolyte with boric acid with a little bit of epsom salt. as an experiment.
but that didn't SEEM to do a lot? I'm not even sure. it kinda works about the same. maybe slightly higher terminal voltage?
And it seems I get modestly higher voltage and runtime now. It's getting kinda to the point where its not gaining a lot of capacity anymore. and its just the internal resistance somewhat holding it back.

Fully charged voltage is just a hair above 2v

 

Ok now the water has gotten very "cloudy" with something grey-white or white-ish I'm not sure what. Any ideas?

Don't consider this an "answer"; it's more of an uneducated guess or a bet, for someone else smarter than me to come along and shoot down or confirm.

Lead sulfate.

 

Do I just discard the lead sulfate when it forms? it slowly dislodges from the electrodes when the battery becomes fully charged without requiring hardly any current. and it dislodges better when charging and discharging slowly Not too fast.

 

Lead sulfate.

In the absence of sulfuric acid?

Probably more like lead and/or tin oxide. Both are insoluble and white in color.

Or possibly carbonates.

 

Similar chemistry:

https://patents.google.com/patent/US20050233216A1/en

 

In the absence of sulfuric acid?

Probably more like lead and/or tin oxide. Both are insoluble and white in color.

Or possibly carbonates.

So, shot down then.
0 points for me.
I don't do chemistry.

 

Whatever it is seems to not want to settle at the bottom. Even after waiting 20+ minutes. The particles are invisible to the naked eye and making the electrolyte "cloudy" looking or foggy.

Update I got a larger container and used like 99.5% boric acid as the electrolyte with a little bit of epsom salt. Mixed thoroughly.
And it holds voltage so well under load now its over 2v with a small DC motor as a load!

 

Also turns out the voltage went too high while charging so its ruined with brown colored junk that inhibits normal charging.
So I have to start over and this time im capping the voltage at 2.5v maximum. never letting it go above that.

 

So, shot down then.
0 points for me.
I don't do chemistry.

I DO understand a bit of chemistry. Given that "baking soda" is listed as sodium carbonate on the container, it is likely that the powder is lead carbonate, which should not be eaten. There might possibly be some chlorides if there is chlorine present in the tap water. But not if distilled water is used.
So you have interesting experiments but not a practical invention.
One more point is that for this to be an educational experiment to do with kids, it is best to have a correct explanation of what is happening, so that some actual knowledge can be passed on.

 

One more point is that for this to be an educational experiment to do with kids, it is best to have a correct explanation of what is happening, so that some actual knowledge can be passed on.

No shit, that's why I'm staying involved in the discussion.

I DO understand a bit of chemistry. Given that "baking soda" is listed as sodium carbonate on the container, it is likely that the powder is lead carbonate, which should not be eaten.

Thanks for providing a more informed 'maybe' than I did; that puts me half a step further away from being so uninformed that my kids would be better off not doing the experiment.

 

I have a few points to note.

1) You are likely producing lead oxide, PbO2. As with all lead compounds, this is poisonous and you should avoid ingesting it or coming into contact with it.

2) Passing electrical current through an electrolyte is electrolysis. This can create bubbles of gas at the electrodes which will impede further electrolysis. This is why it is necessary to agitate the solution.

3) The gases produced can be oxygen and hydrogen. This creates a highly explosive mix of gases. One tiny spark when connecting or disconnecting your wires can trigger an explosion. This experiment should not be conducted at home and without proper precautions in the event of an explosion.
(This is why there is a recommended procedure when attempting to jump start a car with a weak or dead battery.)

 

I'm not consuming the stuff or anything and use gloves when handling any of the materials. so no worries there. I'm not hungry for lead oxides or anything.

I experiemented with more different electrolyte mixtures. and it seems like just using plain and simple magnesium sulfate provided a much better reaction and higher open-circuit voltage. So now I'm sticking with the magnesium sulfate. and maximizing surface area and minimizing the spacing between the electrodes.
Need a very good porous separator that prevents any particles from migrating through them. So like a thick layer of paper towels. or something of the sort.

I'm using distilled water also. No tap water.
I plan on getting some deionized water in the future for an even better result.

the baking soda I was using lists as sodium bicarbonate in the ingrediants. rather than sodium carbonate. (isn't that washing soda?)
but I replaced that with magnesium sulfate instead.

Need to do it at a low current so the electrodes aren't damaged in the forming process. so very slow. Voltage doesn't seem to be the issue. rather limiting the current to something "safe" and not bubbling too violently either. So not consuming electrolyte or water too quickly.

 

Just information.
I measured capacitance between two spoons
under saturated solution of table salt in water:

ADDED:

I dont think thats accurate or "real" capacitance. if the spoons are the same metal not charged or anything. your probably just reading the resistance across the salt-water-metal solution. which is highly conductive and nearly a short circuit like a metal wire.

It is electrical double layer capacitance phenomenon.
Two spoons in solution are supercapacitor.
In this experiment capacitance is about 20 uF for every sq. cm of surface.

https://en.wikipedia.org/wiki/Double-layer_capacitance

https://en.wikipedia.org/wiki/Supercapacitor