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The circuit shown here is more of a drawing rather than a conventional circuit schematic. The big U shape is a container of some kind full of electrolyte. The LED is connected to two leads that go into the bath of electrolyte, each of a different metal.
In a Daniel cell, the bath of electrolyte is split into two parts, one full of zinc sulphate electrolyte, the other full of copper sulphate electrolyte, and a barrier between the two parts that lets the sulphate ions through but keeps the zinc and copper separate. In the copper sulphate bath is a copper electrode, and in the zinc sulphate bath is the zinc electrode, and it produces about 1.1V.
This can also be made with a single bath of one electrolyte, but instead of zinc sulphate or copper sulphate, a weak acid (weak because zinc is so sensitive to low ph that even vinegar dissolves it) or a base can be used. Since a stronger acid/base makes for a better electrolyte, a strong base like lye (sodium hydroxide (Na+ and OH-, or NaOH)) would be an ideal electrolyte since a strong acid would quickly dissolve the zinc.
A homemade battery could be made with lemon juice (acidic, but not strong enough to dissolve zinc), lemons, or potatoes as the electrolyte. If you’re using lemon juice, just add the zinc and copper electrodes to the bath of lemon juice, and make sure they don’t touch. The copper will be positive. If you’re using a lemon or potato, insert the electrodes into the lemon/potato, again without letting them touch.
I made a potato battery using a penny for the positive electrode (zinc is cheaper than copper, so the pennies are mainly made of zinc, but are copper plated, so they still work) and an electro galvanized nail (zinc plated steel nail) as the negative electrode. With 4 potato cells (2 in series to get about 2V, and then 2 of those in parallel to provide current) I was able to dimly light a small red LED. I tried the same with vinegar, but the vinegar dissolved the zinc right off the electro galvanized nails before I could finish the setup which produced an iron-copper cell of about half a volt instead of a zinc-copper cell of about a volt. Also, for the vinegar cell, I used copper wires instead of pennies for the positive electrode.
If lye was used, it might produce a significant amount of current. The copper can be replaced with nickel for a zinc-nickel cell so it can be rechargeable. Then, you might even have a homemade high power (high power as far as homemade goes) rechargeable 1.5V battery (zinc-nickel makes about 1.5V).
For high current, the electrodes should have high surface area to be optimal. For long lasting, the electrodes should have a lot of mass. In regular 1.5V batteries, it’s mainly electrode, and less electrolyte.
Maybe someone could try this out and share their results. Unfortunately, I don’t know of anything nickel around my house, or of any strong bases (probably the strongest is baking soda, and no, I don’t have ammonia), so I can’t make a high power rechargeable battery at home.
I just wanted to share this with everyone. It is both a guide and a description of my own experiments.
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