The following description of
the composition and chemistry of the Alkaline Manganese Dioxide cells
is typical for all alkaline products.
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During cell discharge, the oxygen-rich manganese dioxide is reduced
and the zinc becomes oxidized, while ions are being transported through
conductive alkaline electrolyte. The simplified cell reaction is:
The anode material of the alkaline
cell is a powdered zinc metal. Manufacturing of the zinc powder
is carefully controlled to ensure chemical purity and correct particle
size, resulting in good surface area available during the cell reaction.
This increased surface area provides greater particle to particle
contact within the anode, thereby lowering the cell’s internal
resistance, generating higher power density.
Keeping pace with regulatory requirements worldwide, environmentally
responsive anode designs have been implemented by Duracell.
Click here to request more
information on these cell designs.
The cathode material of the cell is a powdered manganese dioxide
(MnO2), produced synthetically through an electrolytic
process. Its purity and oxygen availability are far superior to
the natural material. This contributes to the cell’s increased
energy density and performance.
Additives are used in the major cathode components to enhance
performance capability. For example, graphite is mixed with the
manganese dioxide to improve conductivity. When mixed with the other
ingredients, the electrolytic manganese dioxide provides a cathode
of excellent conductivity to assure good cell performance over a
wide range of temperatures and discharge rates.
The electrolyte consists of a concentrated aqueous solution of
potassium hydroxide (KOH) to which zinc oxide is added to retard
corrosion of the zinc. This inhibits the dissolution of the zinc
anode and extends the shelf life. In some cell designs, a gel-type
electrolyte is formed by the addition of a gelling agent.
This electrolyte is alkaline (basic) in contrast to the electrolyte
of regular zinc-carbon cells, which is acidic. The concentrated
potassium hydroxide solution offers high ionic mobility with a low
freezing point.
ZnO
+ Mn2O3
