# Soil batteries?

In an attempt to demonstrate the basic principles of common batteries, my teacher assigned me to demonstrate a simple experiment to the kids at the elementary school. A tank filled with saltwater, copper ring used as cathode, cola tin as anode and a motor is powered etc. Surprisingly one little guy there asked if we could use unprocessed soil with natural salts and follow the same technique on a large scale.

I am not keen on disappointing future (maybe) scientists so I answered: yes, but using the soil as an electrolyte is, as it seems inefficient. My teacher said I should search and come with a whole answer so here I am. What about on other worlds? What about on mars? Perhaps using supercritical $\ce{CO2}$ could be the thing. Can a soil battery be useful at all? I like the concept.

• Great question. Galvanic corrosion in soils in a big deal - see this slideshow for a decent overview - and the setup of the "battery" is essentially with soil (usually hydrated to some extent) taking the place of the aqueous salt bath electrolyte. – Todd Minehardt Nov 15 '15 at 16:37
• The slideshow was very useful for my overall search. Thank you for commenting – JohnerzZ Nov 16 '15 at 12:02