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How does a fuel cell work?

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Quick answer

A fuel cell works by combining hydrogen and oxygen to make electricity, with only water and heat as byproducts. Unlike a battery, it doesn't run down — it keeps producing power as long as you supply fuel. Hydrogen enters one electrode, oxygen (from air) the other.

Step by step

  1. Hydrogen enters one electrode, oxygen (from air) the other.
  2. The hydrogen splits into protons and electrons; the electrons flow out as current.
  3. Protons cross a membrane and recombine with oxygen to form water.
  4. The only exhaust is water vapor and heat — no carbon emissions.
  5. It keeps generating power as long as fuel flows, unlike a draining battery.

People also ask

How is a fuel cell different from a battery?
A battery stores a fixed amount of energy and runs down; a fuel cell makes electricity continuously as long as you feed it hydrogen and oxygen.
What does a fuel cell emit?
Just water and heat — there's no carbon dioxide, which is why hydrogen fuel cells are promising for clean transport.
Where are fuel cells used?
In some cars, buses, backup power systems, and spacecraft — anywhere clean, continuous power is valuable.

Part of the guide: Energy & Electricity at Home →