AQA GCSE Chemistry

Revision Notes

5.2.2 Fuel Cells

Hydrogen Fuel Cells

  • A fuel cell is an electrochemical cell in which a fuel donates electrons at one electrode and oxygen gains electrons at the other electrode
  • These cells are becoming more common in the automotive industry to replace petrol or diesel engines
  • As the fuel enters the cell it becomes oxidised which sets up a potential difference or voltage within the cell
  • Different electrolytes and fuels can be used to set up different types of fuel cells
  • An important cell is the hydrogen-oxygen fuel cell which combines both elements to release energy and water

Hydrogen-oxygen fuel cell, IGCSE & GCSE Chemistry revision notes

Diagram showing the movement of hydrogen, oxygen and electrons in a Hydrogen-Oxygen fuel cell

Exam Tip

In fuel cells the polarity on the electrodes are the other way around: the anode is the negative electrode and the cathode is the positive electrode.

Comparing Cells

Advantages

  • They do not produce any pollution
  • They produce more energy per kilogram than either petrol or diesel
  • No power is lost in transmission as there are no moving parts, unlike an internal combustion engine
  • No batteries to dispose of which is better for the environment
  • Continuous process and will keep producing energy as long as fuel is supplied

Disadvantages

  • Materials used in producing fuel cells are expensive
  • High pressure tanks are needed to store the oxygen and hydrogen in sufficient amounts which are dangerous and difficult to handle
  • Fuel cells are affected by low temperatures, becoming less efficient
  • Hydrogen is expensive to produce and store

Exam Tip

You should be able to state 3 advantages and 3 disadvantages of the hydrogen cell.

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.
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