Cathode vs Anode: What’s the Difference?

PDF download Download Article
How cathodes and anodes interact inside of a battery
PDF download Download Article

You’re putting new AA batteries inside of your remote, when all of the sudden, you stop and think, “How do these work?” Whether you’re just curious about how batteries are made or you’re studying for a chemistry quiz, cathodes and anodes are important concepts that anyone can learn. To understand the differences between them as well as how they interact, read on!

Things You Should Know

  • Cathodes are positive electrodes that receive electrons.
  • Anodes are negative electrodes that release electrons.
  • Inside of a battery, anodes and cathodes are connected by a metal conductor to pass electrons.
Section 1 of 6:

Cathode Definition

PDF download Download Article
  1. Also called an oxidizing electron, a cathode acquires electrons from an electrochemical reaction (usually inside of a battery). The cathode receives electrons from the anode. [1]
    2. Advertisement
Section 2 of 6:

Cathode Properties

PDF download Download Article
  1. Typically, this is a metal like copper oxide, graphic oxide, or lithium oxide. In batteries, cathodes have to be stable when in contact with electrolytes, since that’s what aids in the electrochemical reaction. [2]
Section 3 of 6:

Anode Definition

PDF download Download Article
  1. Also called the reducing electrode, an anode oxidizes during an electrochemical reaction. As it oxidizes, it releases the electrons that the cathode then acquires. [3]
    • If you’re working on a water heater, you may have heard the term “sacrificial anode.” The sacrificial anode is a metal rod that sits inside of your water heater. It attracts particles (like iron or limestone) and corrodes over time, helping the water heater tank itself avoid corrosion.
    2. Advertisement
Section 4 of 6:

Anode Properties

PDF download Download Article
  1. Typically, they’ll be made of lithium, zinc, graphite, or platinum. Anodes must have good conductivity so that they can release their electrodes and pass them to the cathode. [4]
Section 5 of 6:

How Cathodes and Anodes Interact

PDF download Download Article
  1. The conductor is typically a metal wire or metal tube that runs from the cathode to the anode. If the battery has a charge, the anode releases electrons that then run along the conductor and into the cathode. The cathode then acquires those electrons. [5]
    • Once the anode erodes completely (meaning it releases all of its electrons), the battery will die or lose charge.
    • This conductor is also sometimes referred to as an “electrolyte.” While electrolytes usually refer to a liquid conductor, inside of batteries, the electrolyte is a solid conductor.
    2. Advertisement
Section 6 of 6:

Cathodes and Anodes in Batteries

PDF download Download Article
  1. Take a look at a battery, any kind. You’ll notice a small plus sign, or positive sign, on one side. This is where the cathode is: since it’s a positive electrode, it’s always indicated by the positive sign. [6]
  2. Now, check out the other side of the battery, and look for the small negative, or minus sign. This is the anode. Since it’s a negative electrode, it’s indicated by the negative sign. [7]
    • It’s important to know where cathodes and anodes are, especially if you’re jump-starting a battery (like in a car). Attaching the jumper cables to the cathode and anode connections in the right order is crucial for a clean charge.
    • You can also find cathodes and anodes in other utilities, like water heaters and fluid tanks.
    3. Advertisement

Expert Q&A

Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Submit
      Thanks for submitting a tip for review!

      You Might Also Like

      How to
      Read a Multimeter
      How to
      Tell Which Way Round a Diode Should Be
      How to
      Set an Intermatic Timer
      How to
      Fix Exposed Electrical Wire
      How to
      Straighten a Wire
      How to
      Reset a GFCI Outlet
      How to
      Pull an Electric Meter
      How to
      Change a Circular Fluorescent Light Bulb
      How to
      Fix Loose Outlets and Plugs
      How to
      Remove a "Knock Out" from an Electrical Box
      How to
      Hang a TV on a Plaster Wall
      Quick and Easy Ways to Repair a Blown Fuse
      How to
      Restore a Brass Lamp
      The Best Methods for Charging a Lead Acid Battery
      Advertisement

      Expert Interview

      Thanks for reading our article! If you’d like to learn more about electrical maintenance, check out our in-depth interview with Richard Taylor .

      References

      1. ↑ https://sc.edu/study/colleges_schools/chemistry_and_biochemistry/internal/research_groups/andrew_b_greytak/docs/which_is_the_anode_abg.pdf
      2. ↑ https://sc.edu/study/colleges_schools/chemistry_and_biochemistry/internal/research_groups/andrew_b_greytak/docs/which_is_the_anode_abg.pdf
      3. ↑ https://sc.edu/study/colleges_schools/chemistry_and_biochemistry/internal/research_groups/andrew_b_greytak/docs/which_is_the_anode_abg.pdf
      4. ↑ https://sc.edu/study/colleges_schools/chemistry_and_biochemistry/internal/research_groups/andrew_b_greytak/docs/which_is_the_anode_abg.pdf
      5. ↑ https://batteryuniversity.com/article/bu-104b-battery-building-blocks
      6. ↑ https://batteryuniversity.com/article/bu-104b-battery-building-blocks
      7. ↑ https://batteryuniversity.com/article/bu-104b-battery-building-blocks

      About This Article

      Thanks to all authors for creating a page that has been read 8,391 times.

      Reader Success Stories

      • Anonymous

        May 26

        "I am doing an FFA project on dirt batteries, and it helped me understand the difference between the cathode and the ..." more
      Share your story

      Did this article help you?

      Advertisement