Why do we need to supply air to the cathode of a hydrogen fuel cell

[srinaath]

I am trying to understand the working of simple hydrogen fuel cell.
We have anode (negative terminal), cathode (positive terminal), catalyst at anode to separate negative and positive ions of hydrogen atoms and electrolyte which allows only positive ions.

We will be sending hydrogen fuel at anode where both positive and negative ions separated. electrons goes through external wire providing electricity. Also i read that we will be sending air to cathode. Why is that required? I mean without air won't the system still work? positive ions will still travel though electrolyte

Kindly provide me some insight.

 

[Bystander]

positive ions will still travel though electrolyte

Producing/yielding what?

 

[Borek]

Start with the reaction equation.

 

[sophiecentaur]

positive ions will still travel though electrolyte

There is a limit to how many of those ions can accumulate in anyone place. You need to provide electrons to neutralise those positive ions. Oxygen will do that for you and hey Presto - you have neutral water.

 

[Windadct]

At the end the equations must balance! --- Electrons that come out of the cell must return! H2 in one side and gives up an electron, and O2 in the other and takes an electron - when they meet in the middle - they get happy (lower energy state) and make water.