INTRODUCTION TO WATER ELECTROLYSIS

We have explored the basic principles. Now meet the four technologies we will study individually.

So far, we have used a simplified electrochemical cell to understand water electrolysis.

We have seen that electrical energy drives reactions at two electrodes, producing hydrogen at the cathode and oxygen at the anode.

Real electrolysers can achieve this using different electrolytes, cell structures and operating conditions.

In ElectrolyserPy, we will explore the following four water electrolyser technologies.

All four use electrical energy to convert water into hydrogen and oxygen.The overall reaction is shared. The way each cell carries charge and supports the electrode reactions differs.

For each electrolyser, we will explore:

• Its structure: the components and how they fit together.
• Its electrolyte: the medium that provides ionic conduction.
• Its charge transport: where electrons and ions move.
• Its electrode reactions: what happens at the anode and cathode.
• Its material pathways: where water or steam enters and where products leave.

You do not need to memorise the differences yet.

First, we will explore each technology individually using diagrams, animations and guided activities.

After all four lessons, we will bring them together in an animated comparison to explore their similarities and differences.

We begin with Proton Exchange Membrane Water Electrolysis.

Let us look inside a PEM water electrolyser and follow the journey of water, electrons, ions and gaseous products.