Fuel Cells (AQA GCSE Chemistry) : Revision Note

Hydrogen fuel cells

How does a hydrogen fuel cell work?

• 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

Fuel cell diagram

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

Comparing cells

Advantages of hydrogen fuel cells

• 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 of hydrogen fuel cells

• 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