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In chemistry and electrochemistry, any device which converts chemical energy into electric energy is termed a battery. The battery usually is a group of two or more galvanic cells capable of converting energy, and generally, it is applied to a single cell.
The batteries are commonly divided into two categories:
- Primary cell (primary battery)
- Secondary cell (secondary battery)
Primary cell is also known as the primary cell. The redox reactions proceed in only one single direction in the primary cell. After a certain time, the reactants in these primary batteries are consumed, usually rendering them dead. If the chemical inside the primary battery is exhausted, it cannot be used further for any purpose.
The dry cell is a good example of a primary cell; household batteries are commonly used in the home to power small things like TV remotes, clocks, small machines. Zinc works as the anode, and carbon rods act as a cathode in primary cells. A kind of manganese dioxide mixture in powder form is placed around the cathode. The given space between the container and the rod is filled with ammonium chloride and zinc chloride.
Difference between primary and secondary cells
| Primary cells | Secondary cells |
1. | It is high in energy density and very slow in Discharge and very easy to use. | They have less energy density. |
2. | There is no presence of fluid in the cells and also known as dry cells | There is the presence of wet cells like liquid cells and molten salts with different compositions. |
3. | It is very high in internal resistance. | It is low in internal resistance. |
4. | It consists of irreversible chemical reactions. | It consists of a reversible chemical reaction. |
5. | It has a smaller and lighter design. | It has a more complex design. |
6. | It is cheap initially. | It is expensive initially. |
Example of primary cell
Below are the examples of primary cells.
Dry Cell
The dry cell is a good example of a primary cell, household batteries are commonly used in the home to power small things like TV remotes, clocks, small machines. Zinc works as the anode and carbon rods act as a cathode in primary cells. All around the cathode, a kind of manganese dioxide mixture in a powder form is placed. The given space between the container and the rod is filled with ammonium chloride and zinc chloride.
Mercury cell
It is another good example of a primary cell or battery as zinc. Mercury amalgam is purposely used as an anode and carbon as a cathode. Therefore, the mixture paste of HgO is further used as an electrolyte. A device that needs a comparatively low electric current supply primary cells are used like hearing machines, TV remotes, watches, clocks.
The reaction of primary cells
Following is the reaction that takes place in these primary cells:
At Anode
Zn(s) → Zn2+ (aq) + 2e–
At Cathode
2e– + 2 NH4+ (aq) → 2 NH3 (g) + H2 (g)
2 NH3 (g) +Zn2+ (aq) → [Zn (NH3)2] 2+ (aq)
H2 (g) + 2 MnO2 (S) → Mn2O3 (S) + H2O (l)
Hence, the whole equation of this primary cell will be like this:
Zn(s) + 2 NH4+ (aq) + 2 MnO2 (S) → [Zn(NH3)2] 2+ (aq) + Mn2O3 (S) + H2O (l)
Household batteries
Household batteries are known as the common man as they are commonly used in home appliances like clocks, torches, remote, camera, small machines. These batteries are further classified into two sub-categories, namely rechargeable and non-rechargeable.
- Examples of rechargeable batteries (Nickel) are cadmium batteries & lithium-Ion.
- Examples of non-rechargeable batteries are silver oxide, alkaline & carbon zinc.
Industrial Batteries
All the heavy-duty requirements are classified under industrial batteries. Because industries’ workload is heavy and has to be done in industrial batteries. The amount of electric current required is too heavy and powerful. Some of their applications are railroad, backup power, and similar big requirements in companies.
Some of the examples of such batteries are:
- Nickel Iron
- Wet Nickel Cadmium (Ni-Cd)
Vehicle Batteries
Comparing it with industrial batteries, these are easier to use and considered less complicated. All motorcycles, boats, and other vehicles have these vehicle batteries because they need less force to run, unlike industrial batteries.
The lead-acid battery is the most important example of vehicle batteries.
Conclusion
The battery is also known as a cell which consists of a cathode, or a positive plate, similarly on the other hand it consists of an anode or a negative plate. A primary battery is also known as a primary cell. In primary batteries, the redox reactions proceed in only one single direction.
After a certain period of time, the reactants in these primary batteries are consumed, usually rendering them as dead. The secondary battery is also known as the secondary cells and can be used again after bypassing of current through the electrodes that are present in the opposite direction which means from the negative terminal to the positive terminal.
