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Drawing out the facts
via Naked Science Scrapbook
Hello and welcome to the Naked Science Scrapbook from the nakedscientists
this time they're answering the question "How does the fuel cell work?"
fuel cells may be the energy source of the future for all sorts of gadgets and vehicles
all cars, laptops and even surveillance aircraft
but What are they and How do they work?
many of our current ways of generating electricity including coal-fired power stations
and nuclear power convert the energy in a fuel into electricity
by first, converting the energy to heat which drives an engine that produces the electricity
which isn't very efficient
a good car engine is only about 30% efficient
A fuel cell is a device that uses a chemical reaction to create electricity directly from the fuel
and these can show up to 80% efficiency
the classic example of a fuel cell is a hydrogen fuel cell
which takes advantage of the facts that when you react hydrogen and oxygen to produce water
energy is released
if you ignite the hygiene and oxygen
the energy is released in a distorted explosion or in small quantities
as the squeaky pop when you hold the lips plin at the end of the...with hydrogen
but if you clever with your chemistry
energy can be released in a more controlled if slightly less fun way
This is where the fuel cell comes in
In a fuel cell it's possible to break the reaction into 2 hubs
by using membrane to keep the two gases apart
on one side hydrogen molecules loose electrons to the anode to form H+ ion
which defused through the electrolytes in the center of the cell
on the other side these H ions react with oxygen
and gain electrons from the cathode to produce water
for this to happen electrons have to flow from the anode to the cathode
in an electric current
so fuel cell works just like a battery with a much higher energy capacity
that you can recharge by adding more hydrogen
if you force the electrodes to go in the opposite direction by applying a voltage
you can actually split the water back into hydrogen and oxygen again
which is called electronlysis
there are other types of fuel cell that use different electrolytes
Alkali cells use KOH as the electrolytes and in fact this type of fuel cell
powered the electrical systems on the Apollo Moon Rocket
and the astronauts drank the water they produced (^_^)
Some fuel cells you Solid oxide electrolytes and run on natural gas
rather than hydrogen
these operate at very high temperatures over 1000 oC
but don't have to potential problem of leaking electrolytes
they could in fact easily be used your water boiler at home to heat the water
using the waste heat produced
instead of a metal elements
and at the same time generating electricity for you
There are problems with fuel cells however
particularly when it comes to using them for something like the car
One of the main issues is that many fuel cells run on hydrogen - a gas
this is pretty hard to carry around with you in your car
as it would have to be contained in heavy pressurized tanks
Plus hydrogen itself is as we saw pretty explosive
They are not necessarily the safest thing to be carrying around in your car
One solution to this is to use liquid fuel like methanol
So, we are already seeing fuel cells in some applications
but there are still problems and compromises on efficiency, temperature, and electrolyzing fuel sources
that need to be worked on before we all start using fuel cells in our daily lives
That's it for this time.
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