Alkaline batteries are the long lasting battery type containing alkaline chemicals (chemicals that have pH greater than 7). These are the most popular small scale power plants for our favorite devices. These batteries are usually disposable (single-use, primary batteries), yet rechargeable versions of alkaline batteries are also available (read more about single-use and rechargeable batteries here).
How do alkaline batteries work?
Each battery needs two electrodes – a cathode and an anode along with electrolyte. The flow of electrons occurs between the electrodes (anode and cathode) via electrolyte, thus creating a closed circuit that uses up the electrolyte’s chemical energy while producing electrical energy. The process remains same for all types of batteries, whether alkaline or zinc-carbon.
Construction
In an alkaline battery, Manganese dioxide is used as the cathode (positive electrode). It is a natural mineral (pyrolusite) and is being used in its powdered form. Graphite is likewise added to the cathode, to enhance its conductivity.
Zinc powder makes up the negative terminal (anode) of the battery. Zinc is being used in the powdered form because this increases the surface area, thus accelerating both the flow of electrons and the rate of reaction. At times, even Zinc oxide is added in order to limit anode corrosion.
Finally, Potassium hydroxide, also known as potash lye or caustic potash, is the compound used as the electrolyte in an alkaline battery.
Advantages
a) Double the energy density than zinc carbon Leclanché cells
b) Four to nine times longer life than the equivalent Leclanché cell
c) Suitable for high drain rate applications
d) Less leakage than Leclanché cells
e) Made from non toxic chemicals
f) Good shelf life
g) Constant capacity over a wide range of current drains
h) Better low temperature performance than zinc carbon; continues to function in sub-zero temperatures
i) Available in multiple sizes (AAA, AA, D, C & 9Volt)
j) Low cost
Applications
a) Flashlights
b) Toys
c) Clocks
d) Remote controls
Related Articles:
