[Lavaguava]

Hello, this is my first post. I am interested in electrochemistry, having being into electronics a while, I have discovered that batteries are very interesting. I have been playing around with iron carbon, aluminium carbon, hydrgogen-oxygen and various dual carbon chemistries. The Iron has been the most successful so far, achieving 1.14V open for several weeks and still going. I got into electrochemistry after placing my multimeter terminals across my hands accidentally while having eczema cream on. I noticed a voltage present, I now know this is due to the slight imbalance of cream concentrations between my hand and the terminal were aluminium, so one of them as being oxidised at a greater rate than the other. When I measured the voltage, I realised, it is so simple to make a battery! I'm an enjoying it greatly, and want to go further.

I was trying different aqueous salts the other day, first trying sodium bicarbonate and then sodium citrate, produced by mixing the sodium bicarbonate with orange juice. The sodium citrate is now in a aluminium-carbon cell, producing a constant 0.95V open cell voltage for the past week, it was charged from a nine volt. I have access to a few elements and chemical compounds, iron, aluminium, (edit: and copper, carbon(graphite)), other relatively safe materials that I can buy online, along with what I can find in the kitchen, sodium bicarbonate, acetic acid solution, citric acid solution, sodium chloride and others. I can't use bleach for any chemical processes because my parents won't let me. I also have access to deodorants and moisturisers, which makes electrolytes easy to work with as they are pre gelled due to the inert parrafin based components.

What can I do now? I would like to look into more exotic electrolytes, aqueous salts are all I have used so far. I have read that alcohols and some oils can form electrolytes. Can anyone suggest something that fulfils these criteria:

Are not dangerous (NFPA 704 maximum health value of 2)
Are not flammable (so there is no risk of fire from overcharge)
Form electrolytes

I also have some questions about some metals for interesting electrodes, but that is another question.

I hope I have formatted my question correctly, Thanks

[Borek]

I strongly suggest you start not with experiments (although they are fun to do!) but with some reading about redox systems, half cells, Nernst' equation and so on - basic GenChem stuff.

Most non-aqueous electrolytes are difficult to work with, as being less polar than water they won't allow dissolving ionic salts, hindering the electrolyte conductivity and lowering the battery emf under load.

[Enthalpy]

Welcome, Lavaguava!

As a general remark: do not suppose that household products known by some trivial or commercial name are less dangerous. It's quite the opposite. With chemicals, at least you know the composition.

I would know some electrolytes that are used in batteries, but they're less easy to find and they use to work with exotic metals like lithium - hence excluded. The other ones tend to be aqueous; I feel copper sulphate, used with one copper electrode, decently safe. Let's see if other ideas come in.

You could try other metals, the most obvious being zinc. Available for rain pipes, and in some locations as a roof cover or a lightning conductor. Excellent together with graphite: it makes the Leclanché element. Manganese is good too but less available. Tin can be a + electrode.

The next step to a good element would be a depolarizer like MnO₂. Let's see what forums members think of its safety and where to buy it.

You could also experiment various shapes to ease the current flow. For instance, a cloth or blotting paper between metal electrodes is thinner, and you can wrap it all (with two clothes).

[Arkcon]

What you're looking for are called ionic liquids.  Sigma Aldrich publishes app notes on these sorts of topics (its how they advertise the precursors.)   You can search for more such documents, or even subscribe to these free mailings.  http://www.sigmaaldrich.com/technical-documents/articles/material-matters/ionic-liquids-for.html

[Enthalpy]

These two look nicely safe and are used as electrolyte in batteries
https://en.wikipedia.org/wiki/Propylene_carbonate
https://en.wikipedia.org/wiki/Ethylene_carbonate
though, they serve for lithium batteries which are themselves too dangerous. On other batteries, i'm not sure at all that these electrolytes bring anything better than water-based ones.