Topic 5.25-5.27 - Chemical Cells and Fuel Cells
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What does a chemical cell do?
A chemical cell produces a voltage until one of the reactants is used up
How do fuel cells work?
They are supplied by an external source of fuel (e.g. hydrogen [most often used in test]) and oxygen or air. The reaction takes place within the fuel cell to produce a voltage. The oxidation of hydrogen results in water being the only product. 2H2 + O2 –> 2H2O
What are the advantages of fuel cells?
-They produce only water as waste (no pollutants formed) -Keeps producing fuel if it keeps being supplied giving a good supply of hydrogen and oxygen gas -Have a long life compared to other types of cells -Easy to dispose of at end of life
What are the disadvantages of fuel cells?
-Hydrogen is difficult to transport/store as it takes up more storage space than other cells and compressed it is potentially explosive. It is also dangerous to transport/store as it is explosive when mixed with oxygen Therefore, it can’t be used in portable devices. -They are expensive to make -Hydrogen can be extracted from fossil fuels which are non-renewable -Carbon dioxide (a greenhouse gas) may be produced in hydrogen’s extraction -Hydrogen produced by electrolysis is often powered by the national grid, so may not be from a renewable source.