History of electrochemistry
In 1789, Franz Aepinus developed a device with the properties of a "condenser" (now known as a capacitor.) The Aepinus condenser was the first capacitor developed after the Leyden jar, and was used to demonstrate conduction and induction. The device was constructed so that the space between two plates could be adjusted, and the glass dielectric separating the two plates could be removed or replaced with other materials.
Electrolytic capacitor
Although fundamental inventions came from Bell Labs, the inventions for manufacturing commercially viable tantalum electrolytic capacitors came from researchers at the Sprague Electric Company. Preston Robinson, Sprague's Director of Research, is considered to be the actual inventor of tantalum capacitors in 1954. His invention was supported by R. J. Millard, who introduced the "reform" step in 1955, a significant improvement in which the dielectric of the capacitor was repaired after each dip-and-convert cycle of MnO deposition, which dramatically reduced the leakage current of the finished capacitors.