Banner Pictures Explained – Top Row

Baghdad Battery

Discovered in the 1930s, the urn dated back to sometime between 250 B.C. and A.D. 250.  Obviously this was many, many years before modern batteries were invented in the 19th century. The artifact contained a copper pipe with an iron rod in its center; it is possible that these were the electrodes of a battery.  Inside the urn was the residue of an acidic liquid that was possibly the electrolyte and it was capped with an asphalt cork with the iron rod protruding through.  They are believed to have been used by the Parthian civilization that occupied the region during this time period as a source of electricity to plate gold onto silver.  Electroplating requires a small electric current to put a thin layer of one metal , for example gold, onto the surface of another metal, possibly silver.

Volta Pile

The voltaic pile was invented in 1800 by Count Alessandro Volta.  It was Galvani that had earlier discovered that he could make a frog’s legs twitch by placing two dissimilar metal probes against its tissue.  Galvani regarded their activation as being generated by an electrical fluid that is carried to the muscles by the nerves and he termed it “animal electricity”.  Volta disagreed with Galvani and believed that the frog’s tissue served as both a conductor of electricity (what we would now call an electrolyte) and the twitching as a detection of electricity.

In 1800, as the result of this professional disagreement over the galvanic response advocated by Galvani, Volta invented the voltaic pile.  The original voltaic pile consisted of a pile of zinc and silver discs and between alternating discs were cardboard pieces soaked in saltwater. A wire connecting the bottom zinc disc to the top silver disc produced electric current.

The battery made by Volta is credited as the first electrochemical cell. For this, and his other work with electricity, we commemorate his name in the measurement of electric potential called the volt.

Leclanché Battery

In 1866, Georges Leclanché invented a battery that consisted of a zinc anode and a cathode of manganese dioxide wrapped in a porous material.  The electrodes were immersed in a jar of ammonium chloride solution. Similar to its use in lithium-ion cells today, a small amount of carbon was mixed into the manganese dioxide to improve conductivity and increase electrolyte absorption.  The Leclanché cell had a voltage of 1.4 volts. This cell was well received and by 1868 twenty thousand Leclanché cells were being used in telegraph systems. The original Leclanché cells were easily breakable.  Eventually the design was modified into what are known as “dry cells” which became widely used in the first flashlights (1909) and in battery-powered radios in the 1920’s.

Planté Battery

In 1859 Planté’s experiments resulted in the lead-acid battery; the first battery that could be recharged by passing a reverse current through it.  Planté’s first model consisted of two lead sheets separated by rubber strips and rolled into a spiral.  One year later he presented a  multi-cell battery compromised of nine of the lead cells housed in a protective box with the terminals connected in parallel. His battery could deliver remarkably large currents.

Although his battery could deliver large currents, one disadvantage of Planté battery is that it could only supply voltage for a short period of time as the cathode had only a small amount of active lead oxide material available during the discharge reaction. This issue was solved by Camille Faure in 1881; where Faure used a set of electrodes consisting of lead paste spread thinly on the electrode surface, providing better plate efficiency with more lead oxide resulting in a longer discharge.

Edison Battery 1905 Nickel-iron cell

Edison believed that lead-acid batteries were both too heavy and that it was not a good idea to use a corrosive electrolyte.  After much experimentation, which is Edison’s trademark, he developed a working alkaline battery. The Edison cell used an iron anode, nickel oxide cathode, and KOH electrolyte. This cell was extremely simple and rugged in design; and can still be found in some industrial applications today, but it was never able to replace the lead-acid cell as Edison had hope