What is a fuel cell and how does it work?

What is a fuel cell and how does it work?

• A. A device that stores hydrogen in one chamber and oxygen in another; when combined, water is formed and energy is released.
• B. A device that stores electricity chemically.
• C. A device that uses heat to generate electricity through a thermoelectric effect.
• D. A turbine powered by combustion in a closed chamber.

Answer: (B)

The main idea is that a fuel cell is an energy-conversion device, not an energy storage device. It takes chemical energy stored in reactants and converts it directly into electrical energy through electrochemical reactions, ongoing as long as fuel and oxidant are supplied. In a hydrogen fuel cell, hydrogen at the anode is oxidized, releasing electrons that flow through an external circuit to do work, while ions move through an electrolyte to the cathode where they combine with oxygen to form water. Heat is also released in the process. Because the cell continuously uses fresh reactants, it can keep producing electricity as long as fuel and air are supplied; it does not store energy like a battery does. This distinction is why a fuel cell is described as a converter rather than a storage device, and it helps explain why it’s considered a clean energy technology—the main byproduct at the point of use is water.

The main idea is that a fuel cell is an energy-conversion device, not an energy storage device. It takes chemical energy stored in reactants and converts it directly into electrical energy through electrochemical reactions, ongoing as long as fuel and oxidant are supplied. In a hydrogen fuel cell, hydrogen at the anode is oxidized, releasing electrons that flow through an external circuit to do work, while ions move through an electrolyte to the cathode where they combine with oxygen to form water. Heat is also released in the process. Because the cell continuously uses fresh reactants, it can keep producing electricity as long as fuel and air are supplied; it does not store energy like a battery does. This distinction is why a fuel cell is described as a converter rather than a storage device, and it helps explain why it’s considered a clean energy technology—the main byproduct at the point of use is water.