A group of Chinese scientists created electricity with a drop of saltwater being drug across a layer of graphene. When saltwater contacts graphene, an equal charge is created on both sides.
Through testing, the scientists found that by dragging the water across the graphene, a measurable voltage was detected. Electrons in the saltwater were desorbed on one side of the graphene and absorbed on the other side. The quicker the water moved across the graphene, there was an increase in voltage. While the total voltage created was only 30 milllivolts, the scientists are motivated by the potential of this project.
Read more how electricity was created with saltwater and graphene.