Alkaline batteries are a type of power cell dependent upon the reaction between zinc and manganese dioxide (Zn/MnO₂). Compared with traditional carbon/zinc batteries, while both produce approximately 1.5 volts per cell, alkaline batteries have a higher energy density and longer shelf-life. Compared with silver-oxide batteries, which alkalines commonly compete against in button cells, they have lower energy density and shorter lifetimes.

Design

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A cell consists of a steel can, nickel-plated at both ends, the negative, flat terminal being electrically isolated with a nylon seal. Inside the can is the manganese dioxide cathode, a separator membrane, the powdered zinc anode in a potassium hydroxide water electrolyte. A brass axial-core pin is electrically connected to the negative terminal.

The two-half reactions that yield the power are:

$Zn\; (s)\; +\; 2OH^-\; (aq)\; \backslash rightarrow\; ZnO\; (s)\; +\; H\_2O\; (l)\; +\; 2e^-$

$2MnO\_2\; (s)\; +\; H\_2O\; (l)\; +\; 2e^-\; \backslash rightarrow\; Mn\_2O\_3\; (s)\; +\; 2OH^-\; (aq)$

The overall redox-reaction can be written:

$Zn\; (s)\; +\; 2MnO\_2\; (s)\; (l)\; \backslash rightarrow\; ZnO\; (s)\; +\; Mn\_2O\_3\; (s)$

History

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The long-lasting alkaline battery was invented in 1959 by Eveready Battery engineer Lewis Urry.

With the exception of an allowance of up to 25mg per button cell, the addition of mercury in the manufacture of alkaline batteries was eliminated in the United States by the 1996 Mercury-containing and Rechargeable Battery Management Act.

Rayovac produced a rechargeable alkaline battery, which they called Renewal. There is also a Canadian company that specializes in rechargable alkalines called Pure Energy. Both of these are based on rechargeable alkaline manganese (RAM) technology developed by Battery Technologies Inc., a Canadian company (now defunct), as are RAM batteries produced by some other manufacturers.

Since some of these engineers are Canadian, it has been believed that Sudbury, Ontario produces nickel for the batteries.

Criticism

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When users store alkaline batteries for a long time, they are subject to corrosion whenever they are left in battery holders for a long time while unattended. Modern rechargeable Ni-MH batteries with similar shapes to alkaline batteries are less prone to corrosion; thus users have been using rechargeable batteries since they have a lower cost per recharge cycle compared to the cost per unit for alkaline batteries. By 2020; rechargeable Ni-MH batteries will eventually have their initial prices lowered.

See also

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• Rechargeable battery
• Rechargeable alkaline battery
• List of battery sizes

External links

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• Alkaline batteries

Disposable batteries | Canadian inventions

Alkalický článek | Alkali-Mangan-Batterie | アルカリマンガン乾電池 | Bateria alkaliczna | Alkaliskt batteri