Study Guides/Chemistry/What is a Fuel Cell?
Study Guide · Chemistry

What is a Fuel Cell? Working and Uses

A fuel cell is an electrochemical device that directly converts the chemical energy of a fuel (like hydrogen) into electrical energy through a redox reaction, without combustion.

Question (Click to Flip)

What is a fuel cell?

Answer

A fuel cell is an electrochemical device that converts chemical energy of a fuel directly into electrical energy without burning it.

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Key Facts

Byproduct: Only water (H₂O) — zero pollution.

Efficiency: 70–80% (vs 35–40% for combustion engines).

Famous Use: NASA Apollo spacecraft.

Type: Electrochemical cell (not a battery — fuel is continuously supplied).

How Does a Hydrogen-Oxygen Fuel Cell Work?

The most common fuel cell uses Hydrogen (H₂) as fuel and Oxygen (O₂) as oxidant.

  • At Anode (−): H₂ → 2H⁺ + 2e⁻ (Oxidation)
  • At Cathode (+): O₂ + 4H⁺ + 4e⁻ → 2H₂O (Reduction)
  • Overall Reaction: 2H₂ + O₂ → 2H₂O + Electrical Energy

The electrons flow through the external circuit, producing electricity.

Advantages

  1. High efficiency (up to 70–80%).
  2. Zero pollution — the only byproduct is water.
  3. No moving parts, so no noise.
  4. Can run continuously as long as fuel is supplied.

Applications

  • Apollo Space Missions: NASA used H₂-O₂ fuel cells for electricity and drinking water.
  • Electric Vehicles: Toyota Mirai uses hydrogen fuel cells.
  • Backup Power: Used in hospitals and data centers.

Questions and Answers

What is a fuel cell?+

A fuel cell is an electrochemical device that converts chemical energy of a fuel directly into electrical energy without burning it.

What is the byproduct of a hydrogen-oxygen fuel cell?+

The only byproduct is water (H₂O), making it completely pollution-free.

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