Hydrogen–oxygen fuel cells
Introduced| English | Meaning |
|---|---|
| fuel cell/ˈfjuːəl sel/ | An electrochemical device that converts the chemical energy of a continuously supplied fuel and oxidant into electricity. |
Power from hydrogen
- Imagine a battery whose only waste is water. That's a hydrogen–oxygen fuel cell 燃料电池.
- It turns chemical energy straight into electricity.
The only product of a hydrogen–oxygen fuel cell is:
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Hydrogen + oxygen → water.
How it works
- Hydrogen and oxygen are supplied to a fuel cell.
- They react in a controlled way that produces electricity, with water as the only product.
A hydrogen-oxygen fuel cell makes electricity, with water as the only product
Inside a hydrogen–oxygen fuel cell
Step through a fuel cell. Hydrogen and oxygen combine to make water, and the energy of that reaction is released as electricity — with no carbon dioxide.
A fuel cell releases the energy of the reaction as:
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It produces electricity directly.
The overall reaction in the cell is hydrogen + oxygen → ______.
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Water is the only product.
The overall reaction
- The overall reaction is hydrogen + oxygen → water (the same as burning hydrogen).
- But instead of a flame, the energy is released as electrical energy.
Metals and hydrogen form at the cathode; non-metals at the anode
A key advantage of fuel cells over petrol engines is that they:
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The fuel cell itself emits only water.
A drawback of fuel cells is that hydrogen is difficult to store and transport.
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Hydrogen storage is a major challenge.
Advantages and drawbacks
- Advantages: only product is water (no CO₂), efficient, quiet.
- Drawbacks: hydrogen is hard to store and transport, and is often made using fossil fuels.
"Clean" depends on how the hydrogen is made. The fuel cell itself only makes water, but if the hydrogen comes from fossil fuels, the pollution just moves elsewhere. Truly clean needs renewable hydrogen.
You've got it
- a hydrogen–oxygen fuel cell makes electricity from hydrogen and oxygen
- the overall reaction is hydrogen + oxygen → water — water is the only product
- pros: no CO₂, efficient; cons: hydrogen is hard to store and often fossil-derived