Zinc-carbon batteries chemistry

The electrolyte was a solution of ammonium chloride that bathed the electrodes. Like Plante s electrochemistry of the lead-acid battery, Leclanche s electrochemistry survives until now in the form of zinc-carbon dry cells and the use of gelled electrolyte.12 In their original wet form, the Leclanche electrochemistry was neither portable nor practicable to the extent that several modifications were needed to make it practicable. This was achieved by an innovation made by J. A. Thiebaut in 1881, who through encapsulating both zinc cathode and electrolyte in a sealed cup avoided the leakage of the liquid electrolyte. Modern plastics, however, have made Leclanche s chemistry not only usable but also invaluable in some applications. For example, Polaroid s Polar Pulse disposable batteries used in instant film packs use Leclanche chemistry, albeit in a plastic sandwich instead of soup bowls.1... 

Batteries vary in size and chemistry. Shown here are an automobile lead-storage battery, rechargeable nickel-cadmium cells, alkaline cells, and zinc-carbon dry cells. 

The term primary battery is used to describe any single use battery system. These include, amongst others, alkaline-manganese, zinc-carbon, lithium, mercuric oxide and zinc-air chemistries. Primary batteries are lightweight and convenient, relatively inexpensive and eonsequently are used by households throughout the world to power portable electrical and electronic devices, radios, torches, toys and a whole host of other every day appliances. 

Because the introduction of lithium power sources to the electronics industry is so recent, many potential users are not aware that lithium batteries are not all alike. Lithium is only the first name of any lithium power source. Just as there are many zinc batteries available (zinc-carbon, zinc-silver cxide, zinc-mercuric oxide) there are many varieties of lithium system, each with its own peculiar internal chemistry and construction. Several of these systems are briefly described below. 

In this connection, Servos mentions, among others, Robert Bunsen at Heidelberg, who invented the carbon-zinc battery and the spectroscope H. H. Landolt at Bonn, later Berlin, who studied the refractive power of the molecule in relation to the refractivities of its atoms Heinrich Rose at Berlin, who followed up on Berthollet s theory of mass action and Cato Guldberg and Peter Waage in Norway, who did so more thoroughly. See John W. Servos, Physical Chemistry from Ostwald to Pauling, 1115. 

Leclanche cells are the least expensive primary batteries. The first zinc-manganese dioxide cell was developed by Georges Leclanche in 1866. He developed the primary battery with an ammonium chloride and zinc chloride electrolyte, and with a natural Mn02 and carbon (usually acetylene black) cathode inserted into a zinc can. His name is still associated with this chemistry today. The battery reactions are given in Equation 10.1. 

Years ago, college chemistry textbooks used to contain tables listing in order of electrical potential the metallic elements and carbon. For some odd reason, the tables used in schools and colleges today omit carbon. This is even more strange because the most common of the dry cell batteries until only a few years ago, made use of the electrical potential between zinc and carbon-a relationship illustrated by the table. Reproduced below are two such tables, one of which includes carbon. 

Butini found that carbonate of magnesia is more soluble in cold than in hot water. Fyfe confirmed this by quantitative determinations, and found the same behaviour with magnesium oxide and magnesium carbonate. He used iron in place of zinc in voltaic batteries. He published a text-book of chemistry. Fyfe s M.D. dissertation was on respiration and some of Fyfe s experiments on respiration are quoted by Prout. ... 

Often, the consumer is confronted with the need to decide which battery is best to replace an expired battery. It is generally advisable to follow the device manufacturer s recommendation for the chemistry of the battery. For example, if a carbon zinc battery is chosen rather than an alkaline cell because of lower cost, the result may be very poor utilization of the battery if the application is not appropriate and opposes the recommendation of the manufacturer of the device. If a comparison among different battery manufacturers for a given type of battery is desired, there are many independent studies of different batteries available to the consumer. 

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