Technology
How does a fuel cell work?
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.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a fuel cell works.
Step by step
- 1Hydrogen enters one electrode, oxygen (from air) the other.
- 2The hydrogen splits into protons and electrons; the electrons flow out as current.
- 3Protons cross a membrane and recombine with oxygen to form water.
- 4The only exhaust is water vapor and heat — no carbon emissions.
- 5It keeps generating power as long as fuel flows, unlike a draining battery.
Frequently asked questions
- 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.