Difference Between Anode and Cathode

The key difference between anode and cathode is that anode is the positive terminal while cathode is the negative terminal.

Anodes and cathodes are electrodes with opposite polarity. To know the difference between anode and cathode, we first need to understand what they are. Anodes and cathodes are electrodes that are used for conducting electric current into or out of any device that makes use of electricity. An electrode is a conducting material that allows current to pass through it. Electrodes are usually made of metals like copper, nickel, zinc, etc. but some electrodes are also made of non-metals like carbon. Furthermore, an electrode completes a circuit by passing current through it.

CONTENTS

1. Overview and Key Difference
2. What is Anode 
3. What is Cathode
4. Side by Side Comparison – Anode vs Cathode in Tabular Form
5. Summary

What is Anode?

The anode is the electrode at which the current leaves the cell and where oxidation takes place. We also call it the positive electrode. A simple battery consists of three major parts: anode, cathode and electrolyte. Traditionally, the electrodes are at ends of the battery. When we connect these ends with electricity, a chemical reaction starts inside the battery. Here, electrons get disturbed and have to reorganize. They repel each other and move towards the cathode, which has fewer electrons. This balances electrons throughout the solution (electrolyte).

In general, current flows out of cathode when the device is discharging. However, the direction of the current reverses when the device is being charged and the cathode starts to function as an anode while the anode becomes a cathode.

In a primary cell or a battery, the terminals are non-reversible, which means that an anode will always be positive. This is because we always use this device to discharge an electric current. But in case of secondary cells or batteries, the electrodes are reversible as the device discharges, but also receive current for charging.

What is Cathode?

The cathode is the electrode at which current enters the cell and reduction takes place. We can call it a negative electrode as well. However, the cathode can be negative in electrolytic cells and positive in galvanic cells.

The cathode provides electrons for cations (positively charged ions). These ions flow to the cathode through the electrolyte. Moreover, the cathodic current is the flow of electrons from the cathode to cations in solution. However, the terms cathode and anode may refer to different meanings in different applications.

What is the Difference Between Anode and Cathode?

Anode is the electrode at which current leaves the cell and where oxidation takes place while cathode is the electrode at which current enters the cell and reduction takes place. The key difference between anode and cathode is that anode is the positive terminal while cathode is the negative terminal. However, there are also bipolar electrodes that can function as both anodes and cathodes. Generally, anode attracts the anions and cathode attracts the cations, which has led to name these electrodes as such.

Summary – Anode vs Cathode

Anode is the electrode at which current leaves the cell and where oxidation takes place while cathode is the electrode at which current enters the cell and reduction takes place. The key difference between anode and cathode is that anode is the positive terminal while cathode is the negative terminal.

Reference:

1. “Cathode.” Wikipedia, Wikimedia Foundation, 27 June 2019, Available here.

Image Courtesy:

1. “Zinc anode 2” – Original work: File: Zinc anode 2.png by User: MichelJullian (talk)Derivative work: KES47 (talk) – File:Zinc anode 2.png (CC BY-SA 3.0) via Commons Wikimedia
2. “Galvanic cell with no cation flow” – The original uploader was Ohiostandard at English Wikipedia. – Transferred from en.wikipedia to Commons by Burpelson AFB using CommonsHelper (CC BY-SA 3.0) via Commons Wikimedia