Many battery chemistries use alkaline electrolytes but "Alkaline Batteries" usually refers to the Alkaline Manganese Dioxide primary cells described below.
1.5 Volt primary cell
Most popular premium general purpose battery.
In an alkaline cell the electrical energy is essentially derived from the reaction of a metal with oxygen.
The Alkaline Manganese Dioxide battery is a variant on the Leclanché cell. As with the Leclanché cell the electrodes are zinc and manganese dioxide but the electrolyte is Potassium hydroxide (KOH).
Recently rechargeable cells using this chemistry have become available. Known as (RAM) Rechargeable Alkaline Manganese batteries they offer all the features and benefits of Alkaline primary cells, with the added benefit of being rechargeable, but without the disadvantage of "memory effect".
Potassium Hydroxide (KOH)
Potassium hydroxide is the electrolyte used in most primary alkaline cells and Nickel based rechargeable cells such as NiCad, NiMH and NiFe cells. It is also one of the main ingredients in houdsehold bleach, drain cleaners and soft soaps.
Similar to, and interchangeable with, zinc carbon Leclanché cells but with as much as double the energy density.
Four times the capacity of a equivalent size rechargeable Nickel Cadmium or Nickel Metal Hydride cells.
Four to nine times longer life than the equivalent Leclanché cell.
Constant capacity over a wide range of current drains.
Suitable for high drain rate applications.
Good shelf life
Better low temperature performance than zinc carbon. Continue to function in sub-zero temperatures.
Less leakage than Leclanché cells
Available in a wide range of sizes including AAA, AA, C, D and 9Volt sizes.
Suitable for a wide range of consumer applications
Made from non toxic chemicals
Higher cost than the basic competing zinc carbon Leclanché cells
Not normally rechargeable
25% heavier than Leclanché cells
RAM cells have limited cycle life of about 100 cycles and are only available in AA and AAA sizes.
RAM cells can be interchanged with standard alkaline cells (but not mixed in the same application).
Low cost but about 50% higher than zinc carbon, however these cells are more cost effective because of the longer life.
Alkaline cells have now largely replaced Zinc- Carbon primary cells.