Fuel-cell flow

Let’s take a look at that most common of electrical sources, the battery. Batteries usually consist of two metal “poles”, with an acid or salt solution sandwiched between them. The chemical reaction of these components makes electrons collect on the negative (-) terminal of the battery and, when an electrical item is attached to the battery, these electrons are used for power. At the same time, though, the chemical reaction within the battery is continuing, which eventually reduces the difference in charge between the positive (cathode) and negative (anode) poles… and the battery stops producing power.

How about a fuel cell? There are a number of different types of fuel cell, but we’ll look at hydrogen cells here. Fuel cells still work by transferring electrons, but the source of those electrons is different: the electrons are stripped from the hydrogen fuel itself. The fuel cell consists of two catalyst-coated electrodes, separated by a membrane which only allows charged particles to pass through. The two electrodes are also connected to an electrical load, such as a car’s motor. Hydrogen is fed into the cell at one end, where the catalyst prompts the Hydrogen to become positively charged H+. The dropped electron from the Hydrogen is picked up by the electrode (which becomes the negative anode), and used to power the load (i.e. the car). Meanwhile, the positively charged H+ passes through the membrane to the other electrode (the cathode), where it is combined with oxygen from the air, and the returning electrons, to become water.