key term - Proton exchange membrane fuel cells

Definition

Proton exchange membrane fuel cells (PEMFCs) are electrochemical devices that convert chemical energy from fuels, typically hydrogen, into electrical energy through a reaction with oxygen. These fuel cells utilize a solid polymer membrane as the electrolyte, allowing protons to pass while blocking electrons, which forces the electrons to travel through an external circuit to produce electricity. PEMFCs are noted for their high efficiency and low emissions, making them attractive for applications in clean energy technologies.

5 Must Know Facts For Your Next Test

1. PEMFCs operate at relatively low temperatures, usually between 60°C and 80°C, which allows for rapid start-up and operational flexibility.
2. The main byproduct of the reaction in PEMFCs is water, making them an environmentally friendly energy source compared to traditional fossil fuels.
3. PEMFCs have potential applications in various fields, including transportation (like fuel cell vehicles), portable power generation, and stationary power systems.
4. The efficiency of PEMFCs can exceed 60% under optimal conditions, significantly higher than internal combustion engines.
5. Challenges in the development of PEMFC technology include cost reduction of materials (especially catalysts) and improving the durability and performance under various operating conditions.

Review Questions

• How do proton exchange membrane fuel cells convert chemical energy into electrical energy?
  • Proton exchange membrane fuel cells convert chemical energy into electrical energy through an electrochemical reaction between hydrogen and oxygen. At the anode, hydrogen molecules are oxidized, releasing protons and electrons. The protons move through the solid polymer membrane to the cathode, while the electrons travel through an external circuit, creating electric current. At the cathode, the protons combine with oxygen and the electrons to form water as a byproduct.
• What are the advantages of using proton exchange membrane fuel cells over traditional energy sources?
  • Proton exchange membrane fuel cells offer several advantages over traditional energy sources. They operate efficiently at low temperatures and produce only water as a byproduct, contributing to lower emissions and a reduced environmental impact. Their high efficiency can lead to better fuel economy in vehicles compared to internal combustion engines. Additionally, PEMFCs can be used in various applications from portable devices to large-scale power generation, showcasing their versatility as a clean energy technology.
• Evaluate the challenges facing the commercialization of proton exchange membrane fuel cells and suggest potential solutions.
  • The commercialization of proton exchange membrane fuel cells faces challenges such as high costs associated with catalysts like platinum, durability issues under varying operational conditions, and limited hydrogen infrastructure. Solutions include researching alternative catalyst materials that are less expensive and more abundant than platinum. Developing better membranes that can withstand harsher environments can enhance durability. Additionally, investing in hydrogen production and distribution networks is essential for supporting the widespread adoption of PEMFC technology.

Related terms

Electrolyte: A substance that conducts electricity by the movement of ions, facilitating the electrochemical reactions in fuel cells.

Anode:

The electrode in a fuel cell where the oxidation reaction occurs, typically involving hydrogen in PEMFCs.

Cathode:

The electrode in a fuel cell where the reduction reaction takes place, commonly involving oxygen in PEMFCs.