Proton exchange membrane fuel cells

Definition

Proton exchange membrane fuel cells (PEMFCs) are a type of electrochemical cell that converts chemical energy from hydrogen and oxygen directly into electrical energy, using a solid polymer membrane as the electrolyte. This technology is important for its high efficiency and low operating temperature, making it suitable for various applications, including vehicles and stationary power generation. PEMFCs play a significant role in renewable energy systems as they provide a clean energy solution with only water as a byproduct.

5 Must Know Facts For Your Next Test

1. PEMFCs operate at relatively low temperatures (around 60-80°C), which allows for quick start-up times and efficient operation.
2. The main components of a PEMFC include an anode, cathode, and the proton exchange membrane that separates them.
3. The efficiency of PEMFCs can exceed 60%, making them a competitive option compared to traditional combustion engines.
4. These fuel cells are often used in transportation applications, including hydrogen-powered vehicles, due to their lightweight design and quick refueling capabilities.
5. In addition to vehicles, PEMFCs are also being explored for use in portable electronics and backup power systems, showcasing their versatility in energy applications.

Review Questions

• How do proton exchange membrane fuel cells function to generate electricity, and what roles do hydrogen and oxygen play in this process?
  • Proton exchange membrane fuel cells generate electricity through an electrochemical reaction between hydrogen and oxygen. Hydrogen gas is supplied to the anode side of the cell where it splits into protons and electrons. The protons move through the proton exchange membrane to the cathode side while the electrons travel through an external circuit, creating an electric current. On the cathode side, oxygen combines with the incoming protons and electrons to produce water as the only byproduct.
• Discuss the advantages of using PEMFCs compared to traditional combustion engines in transportation applications.
  • PEMFCs offer several advantages over traditional combustion engines. They operate more efficiently, converting a higher percentage of fuel energy into usable electrical energy, which results in better fuel economy. Additionally, PEMFCs produce only water as a byproduct, significantly reducing harmful emissions associated with combustion engines. Their low operating temperature allows for quicker start-up times and less wear on components, contributing to a longer lifespan. These benefits make PEMFCs a more sustainable choice for future transportation solutions.
• Evaluate the potential challenges and barriers facing the widespread adoption of proton exchange membrane fuel cells in various sectors.
  • The widespread adoption of proton exchange membrane fuel cells faces several challenges including high production costs, limited hydrogen infrastructure for refueling, and issues with durability under varying operating conditions. The manufacturing processes for membranes and catalysts can be expensive, which can deter investment. Moreover, establishing a robust hydrogen distribution network is crucial for making PEMFC technology practical for everyday use. Overcoming these barriers will require advancements in technology, reductions in costs, and coordinated efforts across industry stakeholders to create a sustainable hydrogen economy.

Related terms

Electrolyte: A substance that conducts electricity by the movement of ions, which in the case of PEMFCs, is the proton exchange membrane.

Hydrogen fuel: A clean energy source used in fuel cells, where hydrogen is the primary fuel that reacts with oxygen to produce electricity, heat, and water.

Fuel cell stack: A series of individual fuel cells connected together to increase the voltage and power output of the system.