Alessandro Giuseppe Antonio Anastasio Gerolamo Umberto Volta (1745-1827) was born and educated in Rome, Italy. He became professor of physics at the Royal School in 1774 and at the University of Pavia in 1779. He is best known for the development of the electric battery in 1800.
The battery made by Volta is credited as the first electrochemical cell. It consists of two electrodes: one made of zinc, the other of copper. The electrolyte is sulfuric acid or a brine mixture of salt and water. The electrolyte exists in the form 2H+ and SO42−. The zinc, which is higher than both copper and hydrogen in the electrochemical series, reacts with the negatively charged sulfate (SO42−). The positively charged hydrogen ions (protons) capture electrons from the copper, forming bubbles of hydrogen gas, H2. This makes the zinc rod the negative electrode and the copper rod the positive electrode.
We now have two terminals, and the current will flow if we connect them. The reactions in this cell are as follows:
- Zn → Zn2+ + 2e−
- sulfuric acid
- 2H+ + 2e− → H2
The copper does not react, functioning as an electrode for the chemical reaction.
However, this cell also has some disadvantages. It is unsafe to handle, as sulfuric acid, even if dilute, is dangerous. Also, the power of the cell diminishes over time because the hydrogen gas is not released, accumulating instead on the surface of the zinc electrode and forming a barrier between the metal and the electrolyte solution.