The Baghdad Battery (AKA "Parthian Battery") is an artifact discovered in Mesopotamia that could have been made as early as 250 BCE - 224 AD. It seems to have been a electrochemical cell, made from a small terracotta jar holding a copper sheet and iron rod.
That Wikipedia article says, "If [the dating is] correct, the artifacts would predate Alessandro Volta's 1800 invention of the electrochemical cell by more than a millennium."
It's speculated that it was used to electroplate gold onto silver, or maybe to inspire religious awe by mildly electrifying metal artifacts that people could touch -- in otherwords: "Magic."
(Of course i went to Wikipedia to read about something else like 30 minutes before discovering this.)