A Proton Exchange Membrane (PEM) is a type of polymer membrane that conducts protons while acting as an insulator for electrons. It is primarily used in fuel cells, where it facilitates the electrochemical reaction between hydrogen and oxygen to produce electricity, water, and heat. The membrane allows protons to pass through while blocking electrons, which helps generate electrical energy. PEMs are essential components in various applications, including hydrogen fuel cell vehicles and portable power systems. Their efficiency and ability to operate at low temperatures make them suitable for clean energy solutions, contributing to the development of sustainable technologies.