eli5 How does battery work?

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So my understanding is that an battery consists of a negatively charged part positively charged part and something in between them to allow electrical flow.

As far as I understand the electrons flow from the negative part to the positive part

The part I don’t understand is what the electrolyte in between is suppose to do?

In: Chemistry

2 Answers

Anonymous 0 Comments

Short answer is that the electrolyte is what stops the electrons from taking a short cut inside the battery.

A battery is made from two materials, one that really wants to get rid of electrons (the negative side) and one that really wants to absorb them (the positive side). If we just stuck those two materials together in an environment where they could exchange electrons, we’d just have a big chemical reaction and no battery. The sneaky part is to separate them so that the electrons can only get where they want to go by running through a wire to do something useful for us.

However, if we just start pulling electrons off one side, that side will immediately develop a positive charge (because it’s missing electrons) and the positive charge will attract the electrons back and nothing will flow. We need a way to balance the charges out so that the electrons can keep flowing. Enter the electrolyte…the electrolyte provides a way for the positive and negative sides of the battery to trade charge *without* letting electrons go across inside the battery. It’s usually some liquid-ish solution of ions. Thus the only way the reaction can complete is for the electrons to “go the long way”…through our wire.

Anonymous 0 Comments

The electrolyte contains ions that react with the materials of the positive and negative (anode and cathode) parts to produce the electrons that flow round the circuit.

Take a common alkaline battery. (Technically a cell, a battery is a group of single cells)

At the negative cathode, zinc metal reacts with hydroxide in the electrolyte turning it into zinc oxide together with water and releasing two electrons into the circuit.

When those two electrons make it back round to the positive anode they get absorbed by converting manganese dioxide (MnO2) and water to a lower oxide of manganese (Mn2O3) and regenerating the hydroxide ions.

Between them these chemical reactions generate 1.43 volts.

Other cells use different chemical reactions but they all depend basically on an oxidation/reduction pair of chemical reactions releasing electrons at the cathode and absorbing them at the anode mediated by ions in the electrolyte.