Work principle of hydrogen and oxygen fuel cells

Hydrogen fuel cell in his oxygen as the oxidant, in the hydrogen as fuel, and then through a variety of chemical reaction, fuel, in turn, will produce the chemical energy into electrical energy has a battery. Hydrogen fuel cell has a large capacity, high power, high conversion efficiency and power range, and many other advantages. Hydrogen fuel cells and general battery, there is a big difference between general battery of the active material is stored in the battery inside, so the amount of storage of the active material of how much capacity of the battery. And fuel cell active substances can be continuously input.

The classification of the hydrogen fuel cells

Hydrogen fuel cell by cell structure and way of working is divided into ionic membrane type, bacon and three types of asbestos membrane.

1, the ion membrane fuel cells

With a cation exchange membrane of acidic electrolyte fuel cell, modern USES the nafion membrane. Battery discharge, the water is generated on the oxygen electrode, through the wick sucked out of water. The battery work at room temperature, compact structure, light weight, but the ion exchange membrane resistance is bigger, small discharge current density.

2, bacon type fuel cell

Alkaline batteries. Hydrogen and oxygen electrode are double porous nickel electrode (internal and external layer of different aperture), plus platinum as catalyst. Electrolyte solution is 80% ~ 85% of caustic potash, is a solid at room temperature, the battery temperature (204 ~ 260 ° C) for liquid. The battery energy utilization rate is higher, but since the big power consumption, starting and stopping needs a long time (24 hours starting, stopping, 17 hours).

3, asbestos membrane fuel cell

Also belong to alkaline batteries. Hydrogen electrode made from porous nickel and platinum, palladium catalyst and oxygen electrode is porous silver plate, two electrode containing asbestos containing 35% caustic potash solution membrane, again with slotted nickel compression on the plates as current collector, a gas chamber, encapsulated into a single cell. Discharge in water to generate hydrogen electrode side, can discharge by circulating hydrogen, can also use static drainage method. The starting time of battery is only 15 minutes, and instantaneous downtime than lithium iron phosphate batteries to be more environmentally friendly.

The advantages of hydrogen fuel cells

1, material and low price

2, the operation is simple,

3, safety

4, efficient,

5, no pollution

The working principle of the hydrogen fuel cells

Fuel cell is a kind of chemical battery that USES material release of energy in chemical reactions, its transformation into electrical energy directly. From this point, it and other chemical battery such as manganese dry battery, lead battery is similar. When it working need to continuously supply response to its material, fuel and oxidant, it and other common chemical battery is not the same. Because it is the fuel through chemical reactions release of energy into electricity output, so is called a fuel cell. Specifically, the fuel cell is to use the electrolysis of water reverse reaction "generator". It consists of the positive and negative and sandwiched between is the cathode electrolyte plate. Initially, the electrolyte plate is formed by electrolyte into the porous plate, is now in development for direct use of the solid electrolyte.

To the negative supply fuel (hydrogen) at work, to the positive supply oxidant (air, play a role of components in oxygen).Hydrogen at the cathode is decomposed into positive ions H + and electronic e -.Hydrogen ions into the electrolyte and the electrons along the external circuit to move to the anode. Electricity load took in an external circuit. On the positive electrode, the oxygen in the air with the hydrogen ions in the electrolyte absorption on the positive electron to form water. This is the very reverse of water electrolysis reaction process.

Using the principle of fuel cells can continuously at work to the external power, so also can call it a "generator".

Generally speaking, writing chemical reaction equations for fuel cells, need highly pay attention to the acid and alkaline electrolyte. On the positive and negative electrode reaction are not isolated, it often closely contact with the electrolyte solution. Such as oxygen, hydrogen fuel cells, which has two kinds of acid and alkali, the cathode reaction in the acid solution is: 2 h2-4 e - = = 4 h + the positive reaction is: O2 + 4 h + + 4 e ˉ = = 2 h2o.So in alkali solution, then there can be no H +, in acid solution, also can't appear OH ˉ.

If the electrolyte solution is alkali, salt solution is negative reactive as: h2 + 4 oh ˉ 2-4 e ˉ = = 4 h20 is extremely: O2 + 2 h2o + 4 e oh ˉ ˉ = = 4

If the electrolyte solution is acid solution is the cathode reaction is: 2 h2-4 e ˉ = 4 h + (cation), is extremely: O2 + 4 e ˉ + 4 h + = 2 h2o

Memory rule is as follows:

Alkaline conditions, easy to remember the positive of O2 and H2O, e ˉ, 4 oh ˉ coefficient in front of 1, 2, 2, 4, respectively, total reaction equations on minus type can be used again. Under acidic condition, easy to remember negative reactive (h + 4) + (4 e ˉ) = 2 h2, through transposition can get the required equations, with total reactive reduced by the positive reactive type on the same.

Hydrogen fuel cell hydrogen oxygen fuel cell

With hydrogen as fuel, oxygen as oxidant, through the fuel combustion reaction, convert chemical energy to electrical energy battery.

Hydrogen fuel cells work, supplying hydrogen to hydrogen electrode, supplying oxygen to oxygen electrode at the same time. Under the action of hydrogen, oxygen and catalyst on the electrode, by electrolyte, produce water. At this time on the hydrogen electrode has redundant electronics and negatively charged, on the oxygen electrode is positively charged due to lack of electronic. After processing circuit, this is similar to the combustion reaction can be carried out in continuous process.

The electrode reaction

Hydrogen fuel battery (neutral medium)

The positive: O2 + 2 h2o + 4 e - - > 4 oh -

Negative: 2 h2-4 e - - 4 h +

Total reactive: 2 h2 + O2 = = 2 h2o

Hydrogen fuel battery acid medium ().

The positive: O2 + 4 h + + 4 e - - > 2 h2o

Negative: 2 h2-4 e - - 4 h +

Total reactive: 2 h2 + O2 = = 2 h2o

Hydrogen fuel cell (alkaline medium) :

The positive: O2 + 2 h2o + 4 e - - > 4 oh -

Negative: 2 h2-4 e - + 4 oh - > 4 h2o

Total reactive: 2 h2 + O2 = = 2 h2o

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