Chemical cells and fuel cells

In this chapter you will learn:

  1. What are chemical cells?

  2. What are fuel cells?

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.

Fuel cells:

  • 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.