George Leclanche invented the Leclanche battery, an improvement over alessandro volta’s wet cell, and the direct precursor of current battery technology. Whereas Volta used copper or tin as the material for one of his electrodes, Leclanche substituted carbon as the cathode. Although Leclanche’s battery was a "wet" cell, as the electrodes were submerged in an electrolytic solution, his design opened the door for the development of the "dry" cell technology that characterizes modern batteries. The vast majority of batteries currently in common use, powering devices from portable stereos to flashlights, are descendants of the Leclanche cell.
Leclanche was born in 1839 in Paris, France. His parents, Eugenie of Villenuve and Leopold Leclanche, sent him to England for his early schooling, then brought him back to France to attend the Ecole Centrale des Arts et Manufactures. After he graduated in 1860, the Compagnie du Chemin de l’Est hired him as an engineer. Within six years of commencing his career, he had invented the battery that would secure his name in the history of science.
Alessandro Volta invented the first battery, or galvanic cell, in 1798. Dubbed a "Voltaic pile" after him, it consisted of copper (or tin) and zinc (or silver), separated by pasteboard or hide, submersed in an electrolyte of dilute acetic acid. The acid ate the zinc, producing electricity. This represented a significant scientific advancement, as it allowed for the harnessing of relatively large amounts of electricity. Two-thirds of a century later, Leclanche replaced Volta’s copper with carbon, marking the first step toward the modern zinc-carbon battery.
In 1866, Leclanche patented his new type of cell, which consisted of a zinc anode and a carbon cathode submerged in a porous pot filled with an electrolytic solution of ammonium chloride. He also added a "depolarizer" of powdered manganese dioxide to the cathode. In the Leclanche battery, the zinc oxidized (or lost both its electrons) to become a positively charged ion that migrated away from the anode, which retained the electrons, creating a negative charge. This imbalance of negative charge induced the flow of electrical current to the cathode and through an external circuit, if connected. The electrons sacrificed by the zinc combined with the manganese dioxide and water, creating manganese oxide and negative hydroxide ions.
However, this was not the end of the chemical reaction, as the Leclanche battery featured a secondary reaction in which the negative hydroxide ions combined with positive ammonium ions, which formed when the ammonium chloride was dissolved in water to form the electrolyte. The result of this secondary reaction was ammonia and water. The cell, which carried about 1.5 volts (a measure of electricity named after Volta), "died" when the manganese dioxide was completely depleted. His original battery was too heavy and fragile for effective commercial distribution, requiring further design improvements.
The next year, Leclanche resigned his engineering position to dedicate himself to developing his battery design. The year after that, 1868, the Belgian Telegraphic Service adopted the Leclanche battery to power its systems, the beginning of widespread use of the battery (especially in telegraphy, signaling, and electric bell work), prompting Leclanche to establish a factory to produce his cells. One of Leclanche’s improvements was to seal the system in such a way that the outside remained dry, despite the fact that the inside of the battery still relied on the "wet" cell design. In this sense, his design also acted as a forebear of modern battery design.
Other scientists also contributed to the advancement of battery technology. robert bunsen, the inventor of the burner that bears his name, also designed a battery using carbon and zinc electrodes but retaining Volta’s acid as an electrolyte (Bunsen substituted chromic acid for Volta’s acetic acid). J. A. Thiebaut came up with the notion of encapsulating the negative electrode and the porous pot inside zinc, patenting this idea in 1881. Carl Gassner, a German scientist, was responsible for the first "dry" cell that succeeded commercially, thus ushering in the modern era of batteries.
Leclanche died on September 14, 1882, in Paris. He was relatively young, in his early forties, preventing him from making further improvements to his battery design. His brother, Maurice, assumed leadership of Leclanche’s battery-production company.