Fuel cells

constituents of commercial cells
understand the processes of charging and discharging cells

disadvantages of discharging/charging cells.
present the possible improvement of batteries (as in electric vehicles) in terms of smaller size, lower mass and higher voltage
Students can present in free form
Keep 7 key criteria of a great advertisment:
design matters
simplicity is key
reward your target
benefit focus
drama
visualize the benefit
clear reinforcement of your place promise

the benefits and potential risks of fuel cells

burns in oxygen, water is the only product formed.
We can use this reaction to supply electrical energy continuously.
We do this by reaction hydrogen and oxygen in a fuel cell.
A fuel cell consists of two platinum electrodes and an electrolyte.
The platinum (Pt) is coated onto a porous material that allows gases to pass through it.
Hydrogen gas and oxygen gas are bubbled through the porous electrodes where the reaction take place.
Hydrogen gas is bubbled through the negative electrode and oxygen is bubbled through the positive electrode.
There are two main types of fuel cell.
One contains an acidic electrolyte, the other contains an alkaline electrolyte such as a concentrated solution of sodium hydroxide.

hydrogen ions (protons) in the electrolyte:
2H2(g) → 4H+(aq) + 4e-
The released electrons move around the external circuit to the positive electrode.
At the positive electrode oxygen gains electrons and reacts with hydrogen ions from the acidic electrolyte:
O2(g) + 4H+(aq) + 4e- → 2H2O(l)
The hydrogen ions removed at the positive electrode are replaced by those produced at the negative electrode.
The concentration of the electrolyte remains constant.
The overall reaction is:
2H2(g) + O2(g) → 2H2O(l)

ions in the electrolyte and forms water:
2H2(g) + 4OH-(aq) → 4H2O(l) + 4e-
At the positive electrode oxygen gains electrons and reacts with water to form hydroxide ions:
O2(g) + 2H2O(l) + 4e- → 4OH-(aq)
The hydroxide ions removed at the negative electrode are replaced by those produced at the positive electrode.
Again, the concentration of the electrolyte remains constant.
The overall reaction is the same as for the acidic electrolyte:
2H2(g) + O2(g) → 2H2O(l)

fuel cell
non-waste technology
sources of hydrogen
hydrogen stability and sustainability
risks in hydrogen and oxygen production and storage

provide electrical power in spacecraft.
The water produced can be used for drinking.
Fuel cells have many advantages over batteries and petrol-driven engines:
Water is the only product made – no pollutants are formed.
They produce more energy per gram of fuel than other fuels.
They are lightweight.
They don’t need recharging like batteries.
Fuel cell operates with high efficiency.
Fuel cells seem to be the answer to many pollution problems.
The hydrogen and oxygen needed for fuel cells to operate are usually produced using fossil fuels at present.