Early electric battery. Historical artwork of a voltaic pile, the first modern type of electric battery, which was invented in 1800 by the Italian physicist Alessandro Volta (1745-1827). A voltaic pile consists of alternating units of plates of two different metals (here silver and zinc) and a piece of wet cardboard or cloth. A pile of these units makes up the voltaic pile shown here. Wires at top and bottom carry the electric current, produced by a chemical reaction, to power an electrical device. Zinc-silver batteries are one of most efficient types of wet batteries, but due to the high cost of silver are today only used in devices like Mars rovers. Artwork from Scientific Recreations (Tissander Gaston, 1850).