Anode vs Cathode: Definition and Difference

Most people who are rarely exposed to battery terminology, do not understand what anode vs cathode are, and may even confuse them as positive and negative electrodes. This article will introduce to you their working principles and usage scenarios.

Major breakthroughs have been made in the field of rechargeable batteries, and solar battery energy storage systems and electric vehicles have been greatly developed. Therefore, it is increasingly necessary to understand and learn the anode and cathode.

Batteries usually consist of three parts, cathode and anode, and electrolyte.

Anode

During the anodizing process, electrons are released from the external circuit to the cathode. This process is a chemical reaction that generates electricity (electrons).

How does the anode work?

The oxidized metal of the anode, after losing electrons, remains in the electrolyte solvent. In this process, the anode slowly erodes.

Metal wires or metal substances act as conductors that can conduct electricity, connecting the anode to obtain the generated electricity to power the device. Once the anode is completely reacted and corroded, the battery will lose all power.

What is the anode material?

Different types of battery anode materials are also different. Among them, lithium, zinc, platinum, or graphite, these anode has good conductivity and stability, and is easy to produce and lower the cost in technology, and is an efficient reducing agent, resulting in high Coulomb output (electrical energy output).

Cathode

The cathode is the other electrode of the battery, gaining electrons from the external circuit, the anode losing electrons (oxidation), and the cathode gaining electrons (reduction).

How does the cathode work?

The cathode is the electrode that receives electrons. In electrochemistry, the principle of a battery is that a reduction reaction occurs. The anode and cathode are immersed in an electrolyte solution. Current flows from the anode, and the current is transmitted from the conductor wire connected to the anode to the cathode.

What is the cathode material?

Metal oxides are good cathode materials, such as copper, silver, gold, nickel, cobalt, etc. Oxidant materials that can react with the electrolyte in a long-lasting, effective and stable manner can be used as cathode materials.

How to distinguish positive and negative poles?

It is easy to distinguish the positive and negative poles from the appearance of the battery. Usually the battery terminals have a plus sign + and a minus sign -. The plus sign + is the positive pole. And the minus sign – is the negative pole.

Positive and negative electrode

When naming electrodes, positive and negative electrodes are usually used. The electric potential of the positive electrode is higher than that of the negative electrode, regardless of charging or discharging, the positive and negative terminals are fixed:

• Positive electrode: The electrode with a higher potential.
• Negative electrode: The electrode with a lower potential.

How to distinguish anode and cathode?

The anode and cathode change, The same electrode can undergo oxidation reaction or reduction reaction. The anode vs cathode need to consider the direction of electron movement. The direction of electron movement is different during charging and discharging:

Take lithium iron phosphate battery Redox reactions as an example:

• The oxidation reaction obtains electrons: LiFePO4==Li(1-x)FePO4+xLi++xe-;
• The reduction reaction loses electrons: xLi++xe-+6C==LixC6;
• The total reaction formula: LiFePO4+6xC==Li(1-x)FePO4+LixC6.

Anode: The terminal that loses electrons (oxidation reaction)

• When the battery is discharged, the negative electrode loses electrons and becomes the anode;
• When the battery is charging, the positive electrode loses electrons and becomes the anode.

Cathode: The terminal that receives electrons (reduction reaction):

• When the battery is discharged, electrons are gained from the positive electrode, which is the cathode;
• When the battery is charged, electrons are gained from the negative electrode, which is the cathode.

Related article about future batteries:

• Will Sodium ion Battery Change the Batteries Industry?
• Why Develop Solid State Battery?

Why is it important to distinguish between anode vs cathode of a battery?

It is important to correctly understand the difference between anode vs cathode, so you can correctly install the equipment to match the anode and cathode of the battery. Batteries are consumables, whether in cars, boats, RVs, electronic devices, toys, etc. When the battery needs to be replaced, it can be handled with confidence.

Sometimes the car battery fails and you need to connect other power sources to the car. At this time, you know how to match the anode and positive pole. You can connect them as needed to charge the battery or replace the original battery for discharge.

Summary of anode vs cathode

Most people don’t know the concepts of cathode and anode, mainly because we are not exposed to these terms in life. If you like to perform maintenance on your car, solar system, boat, or RV and want to know how the equipment works, it will be helpful to understand the anode and cathode of the battery. After all, batteries are found in various daily devices.