the problem with these hypotheses is the lack of wiring. a very simple battery is not difficult to make (but pay no attention to the energy density), but making

the problem with these hypotheses is the lack of wiring. a very simple battery is not difficult to make (but pay no attention to the energy density), but making a useful circuit that does anything is pretty hard. the simplest possible useful circuit is a lightbulb which requires ability to create tungston wire, a vacuum, and very thin, precise glass.