Student – Fuel Cells, Energy option, topic 6.2 and 6.6

I am a big believer that of the fact that fuel cells will become much more mainstream in the next fifty years or so and help to overcome some of the potential issues we have with societies reliance on fossil fuels. At the moment, fuel cells are viable but very expensive to produce but my vision is that the energy and automobile companies will begin to invest in the research and development of fuel cells which will drive down the costs, making them much more readily available and cheaper. There, I have said it and in doing so, probably doomed the whole fuel cell business and condemned the world to relying on expensive and polluting fossil fuels…. But never mind my cynicism; let’s deal with what fuel cells are and how they work.

Fuel cells have enormous advantages over conventional ways to generate electricity – firstly, they don’t produce any nasty pollutants – the only product is water (so no CO₂, SO₂, CO, etc)

Secondly, they don’t rely on the production of heat which is then used to turn water into steam and drive turbines – this is an inefficient process. No, the fuel cell produces electricity directly.

So how does it do this? It sounds great, doesn’t it?

Well, first of all it relies on a reaction taking place in alkaline or acidic conditions, typically, sodium hydroxide or phosphoric acid are used. This will also be the electrolyte.

It uses oxygen gas and hydrogen gas as raw materials and these are reacted together to make water and electrons (electricity).

As it is a cell, there will be a positive electrode (anode) and a negative electrode (cathode).

H2 and O2 are pumped into the cell continuously. H2 is added to the negative electrode and O₂ to the positive electrode. Reactions take place athe anode and cathode as follow:

Under alkaline conditions, the reaction at the anode will be:

H₂ + 2OH^– –> 2H₂O + 2e

And under acidic conditions:

H₂ –> 2H⁺ + 2e

Under acidic conditions, the reaction at the cathode will be:

O₂ +2H₂O + 4e –> 4OH^–

And under acidic conditions:

O₂ + 4H⁺ + 4e –> 2H₂O

So, which ever way you look at things, the overall reaction will be:

2H₂ + O₂ –> 2H₂O

So this is a fuel cell but what do you think? As ever, it would be great to read your views on the subject. Will fuel cells become more mainstream in the future or not? If they don’t, what else may take their place? Why may fuel cells not be universally accepted? What do you think?

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