A Proton Exchange Membrane (PEM) fuel cell is an electrochemical device that converts the chemical energy of hydrogen and oxygen into electricity through a series of redox reactions. Unlike traditional batteries, which store chemical energy internally, PEM fuel cells require a continuous supply of hydrogen fuel and oxygen (typically from the air) to sustain the chemical reaction and generate electricity. This ability to produce electricity continuously as long as fuel and oxygen are supplied makes PEM fuel cells a promising and sustainable energy source for a variety of applications, from transportation to stationary power generation. In this post, we will explore what PEM fuel cells are and how they work, delving into their components, operation, and the overall reaction that powers them.
A Proton Exchange Membrane (PEM) fuel cell, also known as a Polymer Electrolyte Membrane fuel cell, generates electricity through a chemical reaction between hydrogen and oxygen. Here’s a detailed explanation of how it works:
The basic components of a PEM fuel cell include the anode, cathode, electrolyte, and catalyst. The anode is the negative electrode where hydrogen gas is fed. The cathode is the positive electrode where oxygen gas is fed. The electrolyte is a proton-conducting membrane that only allows protons to pass through it while blocking electrons. The catalyst, usually platinum, is used to speed up the reaction at the electrodes. 
The working principle begins with hydrogen splitting at the anode. Hydrogen gas is supplied to the anode, where, with the help of a platinum catalyst, hydrogen molecules are split into protons and electrons. The proton-conducting membrane, or electrolyte, allows the protons to pass through to the cathode while blocking the electrons.
Since the electrons cannot pass through the electrolyte, they travel through an external circuit, creating an electric current that can be used to do work, such as powering an electric motor. At the cathode, oxygen gas is supplied. Here, oxygen molecules react with the protons coming through the electrolyte and the electrons coming through the external circuit to form water.
The overall chemical reaction in a PEM fuel cell results in the production of water, electricity, and heat. This makes PEM fuel cells a clean and efficient energy source, providing a sustainable alternative to traditional fossil fuel-based energy systems.
Wettability plays a crucial role in the efficiency and performance of Proton Exchange Membrane (PEM) fuel cells. It affects how well the fuel cell components manage water produced during the electrochemical reactions. Proper management of water is essential to maintain optimal hydration of the proton-conducting membrane while preventing flooding of the electrodes.
If you would like to learn more about how wettability can be studied in batteries and fuel cells, please sign up for the webinar through the link below.
Susanna is an Application Scientist at Biolin Scientific. In her PhD thesis, she developed fabrication methods for a new type of inorganic-organic polymers. Microfabricated polymer chips were utilized as tool for biomolecule separation in analytical chemistry.
