I messed around a bit again and discovered it could be possible to make a rechargeable battery using only metallic nickel sheets as the both electrodes.
electrolyte is a saturated solution of sodium sulfate and sodium carbonate to maximize conductivity as much as possible
(while still being reasonably safe and not scary caustic like potassium hydroxide)
it takes a long time to form the electrodes. many hours and hundreds of charge discharge cycles. but it does indeed work from a small test setup using several stacked sheets of nickel foils with a thin separator such as napkins toilet paper tissue or paper towels.

I would really like to know exactly whats going on though. The positive electrode gradually darkens. and the negative electrode is reduced. and if you swap the polarity. the colors swap.
Some kind of nickel oxide forms that allows a voltage potential between metallic nickel. and the other nickel electrode.

 

Wouldn't it make a lot more sense to try to find answers to these question on a chemistry forum, particularly one that, perhaps, includes a subforum on electrochemistry?

 

All the ones ive looked at seem dead and inactive (one reply a week or less)
Tried looking for discord servers also but didn't find much luck either. Nobody seems interested in electrochemical related activities.

 

If it makes you feel better, I read your posts.

Unfortunately, I (uncharacteristically) have little to say on the subject.

 

it would be great if there were some kind of discord server or actual "electrochemical activities" related forum that is all about diy hobby projects and stuff. but i haven't found anything worth its salt.

 

Picture of pure nickel strip with a dark oxide coating of some sort on it. from sodium carbonate solution and electrolysis. it charges and discharges like a battery.

 

Sounds an awful lot like a nickel metal hydride battery. Just using nickel as the two electrodes. https://en.wikipedia.org/wiki/Nickel–metal_hydride_battery. Thats the best this wire biter's got. As far as the specific chemistry going on, not sure.

 

Yeah it is similar! but waaaaaaay simpler to make compared to the common manufacturing methods. plus allows more potential electrolyte options!
Just cycle the electrodes reversing the polarity dozens to a hundred or so times (or more) to slowly and gradually increase the capacity and performance.
Better performance if you use lead zinc or iron as the negative electrode though.
Even after discharging with a small DC motor until it stopped turning the voltage quickly rebound up to about 1.2 to 1.3 volts!! Very surprising.
Could try using thin sheets of nickel foam and packing a paste of fine nickel powder into the nickel foam and adhering it with some kind of adhesive (maybe wood glue could work ive seen a lot of people use wood glue) or just a tight pressure fit with a suitable separator between the two electrodes.
and do something similar for the negative electrode. to get higher capacity and performance quicker.

 

well get to working then. Thousands of big brains are dumping billions of dollars into battery tech, but if you think you got something novel go to town. Might want to do some academic searches though to see if someone else hasn't already done a lot of the legwork you're describing. The company I work for uses Elsevier and a few others for scholarly articles. Nature is also a good scientific journal archive to look at. If someone else has already done a lot of the legwork you might be able to skip some of the testing you've already done.

 

I messed around a bit again and discovered it could be possible to make a rechargeable battery using only metallic nickel sheets as the both electrodes.
electrolyte is a saturated solution of sodium sulfate and sodium carbonate to maximize conductivity as much as possible
(while still being reasonably safe and not scary caustic like potassium hydroxide)
it takes a long time to form the electrodes. many hours and hundreds of charge discharge cycles. but it does indeed work from a small test setup using several stacked sheets of nickel foils with a thin separator such as napkins toilet paper tissue or paper towels.

I would really like to know exactly whats going on though. The positive electrode gradually darkens. and the negative electrode is reduced. and if you swap the polarity. the colors swap.
Some kind of nickel oxide forms that allows a voltage potential between metallic nickel. and the other nickel electrode.

This is not so very surprising, really.
Consider that the classic lead/acid battery can be created using exactly the same lead for both electrodes. It was the charging process that created the different surface chemistries . At least that is what I recall reading in a 1928 handyman's handbook. I will need to go back and check that again. But it makes sense .

 

I think it could potentially work a lot better on a larger scale. maybe with some form of very thin layer of super fine particles bonded to the surface of some thin perforated or nickel-foam sheets and could potentially last for virtually eternity.

 

Would be cool to have a battery that never needs maintenance and last forever even if the capacity is low. I've been messing around with nickel iron batteries and the hydroxide electrolyte deteriorates very quickly from interacting with carbon in the atmosphere which also passes through the plastic container they are in...

 

I would really like to know exactly whats going on though. The positive electrode gradually darkens. and the negative electrode is reduced. and if you swap the polarity. the colors swap.
Some kind of nickel oxide forms that allows a voltage potential between metallic nickel. and the other nickel electrode.

Ion exchange of valence electrons. That is why they use dissimilar metals for electrodes to enhance it, but at the price of galvanic corrosion. When you use two electrodes the same metal, it operates like a capacitor and ion exchange capacity would be determined by the surface area. Magnesium is another great metal to use as an anode (+) plate due to the weaker valence shell

 

I also had a huge success combining both nickel current collectors with activated charcoal and graphite to form a sort of supercapacitor battery. The electrolyte being sodium sulfate or potassium carbonate should remain relatively more stable than potassium hydroxide. and should be far less likely to degrade or deteriorate.
As a supercapacitor form. if limited to 0.9 to 1 volt. it could be completely sealed and will never deteriorate from absorbing carbon dioxide. so potassium hydroxide might work in that case.
but then also so does sodium sulfate or potassium carbonate. so there's a lot of options.
I find using nickel for the current collectors for some reason provides huge discharge currents with activated charcoal/graphite in a 50/50 mixture ratio Up to 1 amp per farad of capacitance. Potentially more with a more conductive electrolyte is theoretically achievable.
I believe it could be possible to substitute activated charcoal/carbon with a mixture of fine nickel powder and graphite powder to increase conductivity and capacity. and depending which electrode is designated as the positive or negative electrode. could be used to enhance the performance and capacity. or provide a more flat discharge curve closer to a battery.
One could even combine all 3 activated charcoal/carbon with graphite and fine nickel powders in various ratios using both nickel electrodes as the current collectors.
You could potentially achieve very high rate performance in a small size. and decent energy storage. The nickel can provide higher conductivity and contribute to a flatter discharge curve, and the graphite and activated charcoal can provide more surface area and capacity.

Interestingly the electrolyte can be a variety of options too. from neutral to a strong base.
A very large one could undergo potentially tens of thousands to hundreds of thousands of charge discharge cycles with virtually no wear.

 

Got any pictures? Would be cool to see. I'm kind of looking for advise on alternative electrolyte chemistry for the existing Nickel Iron battery technology. I've got a test setup at home and looking to make improvements.

 

I didn't see any stoichiometry in this topic. Do you know how to balance chemical equations and use the table of standard electrode potentials?

 

As others have already stated, you really need a deep understanding, or find someone who does, of electrochemical processes.

We (in this forum) may know some chemistry, but to understand your reaction and ways to optimize it, a deeper knowledge is required.

 

heres a sample picture of some of what ive been working on.
made a pair of graphite and activated charcoal coated nickel current collector strips. I used a 50/50 mixture of graphite and activated charcoal for both
I got about 0.57 farads of capacity worth out of it.
and a maximum current of 500mA. it could be charged and discharged in less than a second.
I used a thin unfolded sheet of napkin as the separator to prevent them from touching and shorting together. and got very high performance. The squares in the background correspond to half an inch in distance to get a sense of size. They are quite small and only about 0.4 inches by 1.25 inches in active material dimensions. and about 0.3mm thickness.

This one is more of a simple supercapacitor. but works great. I used a sodium sulfate electrolyte. but you could use others like potassium carbonate or potassium hydroxide as those would probably work similarly as well.

Nickel seems to behave somewhat special and works very well to get a good performing active material easily.
I roughened the surfaces with some sandpaper before applying. and cleaned with some isopropyl.

 

In the recent past few years I have read about quite a few "game changing" new battery discoveries. And for most of them, they really would produce real benefits in many ways.
Yet not a single one of those new technologies has made it to market yet. Not a single one of about ten I think.
My point being that while interesting experiments can be a lot of fun, it seems that there are a lot of barriers between an interesting, or even exciting, discovery and a marketable product.

 

Also the fact that you can create a working ultra simple rechargeable lead-acid alternative battery by using lead and an alkaline or neutral electrolyte. with decent capacity. good discharge cycles. and decent power output. You can make one the size of an AA battery output just over 10 amps of current with an electrolyte of sodium sulfate and aluminum sulfate. or potassium bicarbonate. or potassium carbonate.
Instead of sulfuric acid. There's literally tons of options and possibilities.
You can get very high power density very easily too by utilizing more thinner parallel electrodes or a cylindrical spiral wound design.
I even found that you can make a rechargeable zinc based battery with an electrolyte of potassium bicarbonate and it will last for hundreds or thousands of cycles without forming dendrites or degrading easily.
it's not hard at all to retrofit an old lead acid battery case with your own battery components.

I created a 16-layer stack of nickel sheets about 2.27 by 2.4 inches in dimensions. as a larger scale version supercapacitor
each about 1mm in thickness with activated charcoal and graphite powder in a 50/50 mix with a sodium sulfate electrolyte. with the tabs parallel and a thin separator for each layer alternatingly
I achieved about 233 farads at 1 to 1.2 volts and about 220 amps.
(that is more amps than you can shake a stick at)
in something you can hold in your hand easily. Put 12 in series and you'll get 12 volts. and enough current to jump start a car.
and it can be charged and discharged near endlessly.