Dry and alkaline primary batteries

Batteries, which are galvanic cells, fall into one of three main types. A primary cell is a battery that cannot be recharged. A secondary cell is a battery that can be recharged and reused. A fuel cell has a continuous input of chemicals (fuel) to produce a continuous output of current. 

As with all commercial batteries, the real cell reaction is complex, and the reactions are approximated as follows. 

Cathode reaction (reduction, electron consumption) Mn02(s)+ H20(1) + MnO(OH)(s)+OH (aq) Cell reaction  

The main problem encountered with this cell is the buildup of Zn and OH at the respective electrodes, which is why the battery is mainly used intermittently. When the battery is not being used the concentrations of these reaction products falls again. This is because the OH ions migrate to the Zn anode where they form ammonia with NH4 ions in the electrolyte  

The concentration of the Zn ions in the vicinity of the anode subsequently drops as a result of reaction with the NH3  

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