Chemical cells and fuel cells

In this chapter you will learn:

Chemical cells:

A chemical cell converts chemical energy into electrical energy.
Chemical cells include the familiar batteries used in everyday appliances, torches, mobile phones and cars.
A non-rechargeable chemical cell produces a voltage until one of the reactants is used up.
The voltage of a chemical cell depends upon factors such as, what the electrodes are made from, and the electrolyte.
More than one cells can be connected in series to make a battery. A battery has a higher voltage than a single cell.
In a simple cell, two electrodes are made from metals of different reactivity immersed in an electrolyte and connected to an external circuit.
Metal with higher reactivity acts as negative electrode.
A voltage is produced due to the difference in the ability of the electrodes to release electrons.

Hydrogen oxygen fuel cell combines hydrogen and oxygen to generate electricity with water and heat.
Fuel cells continuously generate electricity as long as fuel is continually supplied.
In a fuel cell, fuel is oxidised electrochemically instead of being burned.
In a hydrogen oxygen fuel cell, electrolyte in an alkali fuel cell is potassium hydroxide (KOH). The anode is a platinum catalyst. The cathode is also a platinum catalyst.
Fuel cells are used in space vehicles, transportation.
In a spacecraft in orbit, solar cells are used to produce electricity that is used to replace hydrogen and oxygen through the electrolysis of water.
Hydrogen-oxygen fuel cells are an alternative to rechargeable cells and batteries.
The hydrogen oxygen fuel cell is non-polluting, as only water is produced.
Hydrogen fuel cell offers a high level of energy efficiency.
In a hydrogen oxygen fuel cell, hydrogen is explosive and difficult to store.
Hydrogen oxygen fuel cell is very expensive to manufacture.