For a project we're thinking of generating electricity out of wet newspapers. Is that possible? How much current would it generate?
You will need to soak your newspapers in a suitable electrolyte, water will not work. You could try lemon juice as a weak acid (vinegar could work). You will then need two dis-similar metals one for the Anode and the other for the Cathode. Let us say a piece of copper and a piece of zinc (galvanised steel will do). Place the two metals in contact with the sodden newspaper and measure the voltage between the plates. You should get around 0.85V. You will not get much current out of this cell as the internal resistance of the soggy newspaper will be quite high. It should light up an LED.
You could just get a lemon and stick the two metals through the skin into the fruit, dispensing with a messy pile of soggy newspaper.
Once upon a time you might have been able to get a weak voltage from soggy newspapers. The ink that was used had small amounts of various metals that would be conductors. The paper itself was bleached and certain amount would not get rinsed out.
Today the ink is soy based, it does not contain any metal. The paper has little if any chemicals left in it from processing. You could add metal as electrodes and add a electrolyte like acetic acid (citrus juice), but if you do that you don't need the newspaper.
There has been some attempts to use cellulose (paper) with carbon nano tubes suspended in ink for manufacturing batteries, but this is much more the wet newspapers.
It mostly depends on
- the chemicals the newspaper has been soaked in.
- The material of the electrodes placed in/on the newspaper.
I seem to remember a project a while back which used copper and zinc for +/-. Something about the different metal properties allowed electricity to flow. Do some searches with those keywords.
The newspapers themselves won't generate any electricity as they don't react with anything. Batteries are formed by compounds with dissimilar electrode potentials, so you will require some sort of additional reactants (usually metals) that you could keep separate with newspaper. Copper/zinc as Brad mentions are fairly easy to obtain and cheap, though the possibilities are vast (magnesium, lithium, iron, tin, nickel, silver...)
The current any battery generates is based on the speed it can react components, which is governed by the geometry of the cell above all else. If you only know the materials (we don't here anyways), the best you can do is estimate the voltage.
Alternatively, you could use wet newspaper as a spacer for aluminum electrolytic capacitors. Roll up paper-foil-paper-foil, apply a reverse voltage to grow the aluminum oxide dielectric, and presto, capacitor.