In this year's Beijing Olympics by the fuel
laptop battery powered cars in the game had already started to put into operation. As the fuel cell can be chemical energy directly into electricity, will not cause environmental pollution, generally regarded as candidates for new energy vehicles, one.
However, its high price is also astounding: the use of gasoline compared to conventional vehicles
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However, after seven years of study, College of Chemistry and Molecular Sciences, Professor Shobayashi their host team, finally realized the originality of fuel cell technology breakthrough: they have developed the alkaline polymer electrolyte fuel cell, the future is expected to Great amplitude to reduce costs. The results, published in the December 15 issue of "U.S. National Academy of Sciences" (PNAS) on.
The existing proton exchange fuel cell vehicles reason for the price so high, a very important factor, it is because of them use very scarce on Earth, one of the heavy metals - platinum (commonly known as Platinum).
Proton exchange membrane fuel cell works, is the catalyst, the hydrogen of the hydrogen atoms of the two electrons are ionized, the two electrons in the positive, attracted by the positive movement to generate an electrical current, loss of electronic hydrogen ion (proton) is through the proton exchange membrane (ie, acidic polymer electrolyte), in the cathode and oxygen atoms and the electronic re-combination of the water.
Because of this acidic polymer electrolyte fuel
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Zhuang Lin said that, for every 1000 watts of power, you need 1 gram of platinum. If a car needs 60 kilowatts of power to assess, the legitimate need 60 grams of platinum, while a medium-sized buses will need 90 grams of platinum. As the platinum reserves are scarce, so in order to fuel cell driven car cost is often astonishing.
In addition to must be used in the manufacture of platinum, he has added that as the proton exchange membrane fuel cell caused by the instability of platinum wear and tear, should be continually in the course of this additional platinum catalyst. This makes the present with the acidic polymer electrolyte fuel cell cars as a driving force, under normal working conditions, its use of time is often no more than 2000 hours.
In this case, the Zhuang Lin and his colleagues began to turn its attention to alkaline polymer electrolyte batteries, hoping to shake off dependence on the platinum. Because, although alkaline polymer electrolyte will be corrosion of metal, but its corrosive strength of acidic electrolyte smaller than many, many transition metals can be stable under alkaline conditions there.
In fact, in everyday life, we are no stranger to alkaline batteries. And as early as in the sixties and seventies of last century, NASA has been put on the alkaline fuel cell, used in the Apollo spacecraft on the moon.
However, when the alkaline fuel cell applications place from space into the ground, problems follow. Because the spacecraft uses pure oxygen and pure hydrogen, but if you want to use on the ground, alkaline fuel cells, it is necessary to use air instead of oxygen. The air contains carbon dioxide, carbon dioxide will make alkaline electrolyte carbonation, resulting in carbonate precipitation down; In this case, water-resistant air electrode will be destroyed, the electrolyte will leak out.
To solve this problem, scientists have used the alkaline electrolyte is made of solid form, which is alkaline polymer electrolyte. The cation is fixed in the polymer, so which do not generate the carbonate in the liquid phase.
However, the alkaline polymer electrolyte, in the conductivity and stability, as compared with conventional fuel cells, there are still a certain gap. Zhuang Lin and his team achieved a breakthrough among other things, they successfully developed a very stable and high ionic conductivity of the alkaline polymer electrolyte. Test results show that the alkaline polymer electrolyte present in the international arena is optimal.
Zhuang Lin said that to achieve this
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In order to overcome this technical problem, Zhuang Lin and his team, the approach is the surface of the electronic structure of nickel-controlled changes in it greatly enhanced the reaction selectivity. In this way, you can only do hydroxides oxidant but also has antioxidant activity.
However, he acknowledged in an interview, as opposed to already have the decades-old tradition of acid fuel cells, the current alkaline fuel cell output power density, there are still relatively large gap, is still a difference of about one volume level.
Moreover, in view of industrialization is also still far away, is also difficult to estimate precisely this technology in the end bring down the cost of fuel cell vehicles to what extent. But Zhuang Lin stressed that because of this new type of fuel cell completely out of scarce resources for such a dependence on platinum, "the prospects for cost reduction is very optimistic."
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