[dnhz]

> To be clear, the potato is not, in and of itself, an energy source. What the potato does is simply help conduct electricity by acting as what’s called a salt-bridge between the the two metals, allowing the electron current to move freely across the wire to create electricity. Numerous fruits rich in electrolytes like bananas and strawberries can also form this chemical reaction. They're basically nature’s version of battery acid.

That doesn't sound so exciting to me.

[young_unixer]

Isn't that a bit like saying

"The sun is not a light source, it's just very hot, which causes hydrogen to go into nuclear fusion, which releases energy in form of electromagnetic radiation"?

Or is my comparison flawed?

[edrxty]

The energy is coming from metals rather than the potato. The potato simply links them allowing their ions to react and create an electric potential.

[soarfourmore]

Iwish the article described the cost, size, and rarity of the two metals, but instead it focused only on the potato

[amluto]

The actual paper does: https://www.researchgate.net/publication/239391768_ZnCu-vege...

[edrxty]

If you want a deeper dive, the chemistry here is actually really simple and (IMO) very cool.

I'm drawing on some really dusty knowledge here but TL;DR the cells can be modeled as two reactions, oxidation and reduction. One is gaining an ion and the other is shedding one. This is typically shown in the equation as some number of "e-".

Because there are two reactions, each one is described as a half cell and there are tables[1] of all the voltages that these half cells create. Therefore you can mix and match to create batteries of arbitrary voltages, though whether they're practical is another issue.

If you look at the table, you'll notice that some common battery chemistries stand out, like:

Li+ + e− ⇌ Li(s) −3.0401

for lithium Ion batteries (the other reaction adding the last ~.7v to reach the nominal 3.7 cell voltage you're used to). Similarly you can find the half cells that make up a 1.5v alkaline battery[2].

[1] https://en.wikipedia.org/wiki/Standard_electrode_potential_(...

[2] https://en.wikipedia.org/wiki/Alkaline_battery

[samstave]

I don't know why - but this comment makes me laugh

[amluto]

It can’t be quite that simple. I’m not at all an expert in electrochemistry, but you can put pure zinc and pure copper together in a sealed container with nothing else except ideal electrodes until the cows come home, and you will not end up with copper oxides, zinc oxides, or any useful energy output.

[8note]

I mean, just some salty water will do the trick

[sildur]

Not the OP, but now I got it, thanks.

[numpad0]

What it means is that the potato is just working as a media to connect two metal plate and not as a power source. Actual voltage and current is created by the metal plates corroding and melting into potato.

So it’ll be like saying “the atmosphere is not an energy source, it just blows between the sun and solar panels” without understanding what that means.

[cma]

No, the potato is basically acting as a salt bath here. It would be more like thinking the empty space the sun's light travels through is the light source, not the sun.