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Carbon Battery Structure Principle
- Jul 28, 2018 -

The zinc-manganese dry battery is very common in daily life.

Positive material: MnO2, carbon rod

Negative material: zinc sheet

Electrolytes: NH4Cl, ZnCl2 and starch paste

The chemical formula of the battery can be expressed as

(-) Zn|ZnCl2, NH4Cl (paste) MnO2|C (graphite) (+)

Anode: Zn=Zn2++2e

Cathode: 2MnO2+2NH4++2e=Mn2O3+2NH3+H2O

Overall reaction: Zn+2MnO2+2NH4+=2Zn2++Mn2O3+2NH3+H2O

The electromotive force of the zinc manganese carbon battery is 1.5V. The resulting NH3 gas is absorbed by carbon, causing electromotive force to decrease faster. If the highly conductive paste KOH is used instead of NH4Cl, and the positive material is changed to the steel tube, the MnO2 layer is close to the steel tube. This is the structure of an alkaline zinc-manganese dry battery. Because no gas is produced during reaction, the internal resistance is low and the electromotive force is stably at 1.5V.

The carbon battery is a type of single-use chemical energy. It uses manganese dioxide as the positive electrode and the zinc tube as the negative electrode, converting chemical energy to electric energy. In the chemical reaction, because zinc is more active than manganese, zinc loses electrons and is oxidized, and manganese collects electrons and is deoxided.