[Gunner]

This is literally ancient technology. Paper/foil batteries were hot stuff around 1800. Very low current capability but can last for unbelievable lengths of time - sealed systems ran for decades. One sealed electrical bell powered by two of these "dry piles" has been operating since 1840, so long that the bell-ringing ball is wearing away. There was never a use for low-current batteries so the technology faded away... but now that we have circuitry that runs on nanoamps, it might become useful.