Proton exchange membrane fuel cell

Definition

A proton exchange membrane fuel cell (PEMFC) is a type of fuel cell that converts chemical energy from hydrogen and oxygen directly into electrical energy through electrochemical reactions. PEMFCs use a solid polymer membrane as the electrolyte, allowing only protons to pass while blocking electrons, which generates electricity and water as byproducts. This technology is essential for clean energy applications, especially in transportation and portable power systems.

5 Must Know Facts For Your Next Test

1. PEM fuel cells operate at relatively low temperatures, typically between 60°C and 80°C, making them suitable for automotive applications.
2. The efficiency of PEMFCs can be significantly affected by the purity of the hydrogen used, as impurities can poison the catalyst and reduce performance.
3. Water management is critical in PEMFCs, as both excess water and insufficient water can impact cell performance and durability.
4. PEM fuel cells have a quick start-up time compared to other types of fuel cells, allowing for dynamic operation which is beneficial for vehicles.
5. Research is ongoing to find alternative catalysts that can replace expensive platinum to reduce costs and improve sustainability in PEMFC technology.

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 a process called electrochemistry. In a PEMFC, hydrogen gas is supplied to the anode side where it is split into protons and electrons by the catalyst. The protons pass through the polymer membrane to the cathode side while the electrons travel through an external circuit, creating an electric current. At the cathode, oxygen combines with the protons and electrons to produce water, completing the cycle.
• Discuss the challenges associated with using proton exchange membrane fuel cells in practical applications.
  • One major challenge facing proton exchange membrane fuel cells is the reliance on precious metal catalysts like platinum, which increases production costs and limits widespread adoption. Additionally, managing water within the cell is crucial; too much or too little water can lead to decreased performance or even damage to the cell. Furthermore, hydrogen storage and distribution infrastructure needs significant development to support the broad use of PEMFCs in transportation and other sectors.
• Evaluate how advancements in nanomaterials can enhance the performance and affordability of proton exchange membrane fuel cells.
  • Advancements in nanomaterials have the potential to significantly enhance both the performance and affordability of proton exchange membrane fuel cells by improving catalyst efficiency and reducing material costs. For instance, utilizing nanoscale catalysts can increase surface area, leading to better reaction rates and lower amounts of precious metals required. Additionally, innovative nanostructured materials can be developed for more effective water management within the cell. By incorporating these advancements, researchers aim to make PEMFC technology more accessible and economically viable for widespread adoption in clean energy solutions.

Related terms

Electrolyte: A substance that conducts electricity by the movement of ions and is used in fuel cells to facilitate the transfer of protons.

Catalyst: A material that speeds up the electrochemical reactions in a fuel cell, typically made from precious metals like platinum.

Hydrogen storage: Technologies and materials used to store hydrogen gas efficiently for later use in fuel cells or other applications.