Proton-exchange membrane

Imagine you have a special kind of sponge. This sponge has small holes that only let water through but not other things. Now imagine you put one side of the sponge in a glass of water and the other side in a glass of something else, like juice.

If you rub your finger on the sponge, you will feel a small electric shock. This is because the water and the juice have different charges, like if you rubbed two balloons together and they stick to your hair.

A proton-exchange membrane is kind of like that sponge, but it is made of tiny molecules that can only let protons through. Protons are tiny parts of atoms that have positive charges, like how your hair sticks to the rubbed balloons.

This membrane is used in something called a fuel cell, which is like a really special type of battery. The fuel cell has two sides, with oxygen gas on one side and hydrogen gas on the other. The hydrogen gas goes through the proton-exchange membrane, but the oxygen gas doesn't.

When the hydrogen gas goes through the membrane, it splits up into two parts: a proton and an electron. The proton goes through the membrane, but the electron can't, so it has to go around the outside of the cell.

The electrons are used to power something like a light bulb or a car, and when they get to the other side, they combine with the protons and oxygen to make water. This water goes out of the fuel cell and is safe to drink, just like when you mix water and juice in the sponge, it doesn't make anything dangerous.

So the proton-exchange membrane is like a sponge that only lets protons through, and it helps make electricity in a fuel cell by splitting hydrogen into protons and electrons.