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Imagine, what happened is: you started the electrochemical experience gathered circuit and the battery suddenly "village", and spare batteries no. How can that be? But it's not so bad. Much worse, when the flashlight goes out dark in the evening, but still in the forest. And what a shame if the battery transistor radio fail just at the moment when radio transmit your favorite song, or during the broadcast of a football match. But what can you do...

Meanwhile, something to take you. If spare batteries no, do not rush to throw out the old, and try to "revive".

Many modern batteries - "Crown", "Mars", "Saturn", KBS and other consist of the elements manganese-zinc system. When working the negative electrode of these batteries - zinc glass - gradually, but very slowly dissolved, and the positive electrode is manganese dioxide, Mno2, is reduced to trivalent manganese hydroxide (its formula can be represented as Moon). He gradually covers the grain of the oxide penetrates deep into the grains and closes access to the electrolyte. Still half of the manganese oxide is not used, and the element is no longer working; zinc as by that time there is still more to four-fifths! In short, almost fit the battery have to be disposed of.

But if you remove the "shell" Moon, the electrolyte will again be able to enter the grains and the battery will come alive. Only how to shoot? The easiest way is to knock on a battery as a hammer or stone. Then the grain inside elements will crack, and the electrolyte will be able to penetrate. This method is not particularly good, but in the woods, perhaps the best ever.

If the battery was denied at home, then activated manganese dioxide can be much more effective. In zinc glass batteries punch nail hole and immerse the battery in water. The electrolyte element is not liquid (this would be inconvenient), and thickened. He soak in water, diluted, and it is easier for him to penetrate the grains of manganese dioxide. This simple technique allows you to increase the battery life by almost a third. But it can be simplified.

Fill the battery with water is not necessary. Just enough to punch a hole in the zinc Cup. Manganese oxide in the element is mixed with graphite powder is necessary in order to increase the conductivity. As soon as the air starts to go inside, graphite will absorb oxygen, and along with the manganese dioxide will have one positive electrode, a so - called air, where oxygen is reduced. In short, simple nail turns manganese-zinc element in zinc-air!

Fair to say that after this procedure, the battery will discharge small talk - such are the properties homemade zinc-air element. But to serve will be very long.

And one last thing: make it so that the old battery will be almost as good as new. For this battery, you must charge the electric current, i.e. do it the same way with the battery. The reaction taking place in the battery, reversible, and Noon may again become IGOs2.

Note that the charge can not all the batteries, but only those that are not dried pasta and the housing is not damaged. And charge need not conventional constant current, charge the batteries. In this case, the zinc will be deposited on the body of the batteries in the form of branched filaments-dendrite, and very soon it will cause a short circuit occurs and the battery will be damaged. To charge it the so-called asymmetric shocks. To get it, it is necessary to rectify the alternating current is not fully, for example: to include in the circuit a diode rectifier and a parallel - resistance (about 50 Ohms). The voltage source should be about 12, so using the current directly from the network can not, you need a step-down transformer.

Manganese-zinc elements can be charged up to three times their capacity degrades only slightly. And the small, so-called button elements (they used mercury-zinc system) that allows you to charge up to ten times. But to break their nails or pounding on them with a hammer, there is no point in these items after discharge practically does not remain active substances.

O. Holguín. "Experiments without explosions"
M., "Chemistry", 1986


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2013-01-28 16:48:13
In grade 6 on microelectronics little explained
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