Fuel Cells Flashcards
How are fuels cells provided with fuel ?
From an external source of fuel (eg hydrogen) and oxygen from the air
How does the fuel cell generate electricity ?
By reacting hydrogen with oxygen
The fuel is oxidised electrochemically within the fuel cell to produce a potential difference
What can hydrogen fuel cells be used for ?
To power cars
What is the waste product produced by hydrogen fuel cells ?
No pollutants only water
Write the half equation, at the negative anode, for Hydrogen?
2H2 ——> 4H+ + 4e-
Hydrogen is oxidised
Write the half equation for oxygen at the cathode?
O2 + 4H2 + 4e- ——> 2H2O
What happens to hydrogen?
It is oxidised which produces water
Why are some pros of hydrogen fuel cells ?
- run for alsong as you provide them with hydrogen
- do not get less efficient as they run
- can be a source of drinkable water
What are some cons of rechargeable batteries ?
- will run out and need to be recharged
- store less electricity the more charging cycles they go through meaning they need replacing
What are some cons of hydrogen fuel cells ?
- run off hydrogen which can be explosive and is very difficult to store safely
- produce a low potential difference or voltage so several are needed
What are some pros of rechargeable fuel cells ?
- no dangerous fuels are required
- can produce a greater potential difference than hydrogen fuel cells