What Is the Difference Between Cathodes and Anodes?

Cathode-anode ratio: The relative area of the cathode and anode in a corroded battery has a greater effect than the corrosion rate of the anode. If the anode area is small relative to the cathode, such as a steel rivet on a copper plate, the anode (steel rivet) will quickly corrode. This is because the corrosion current is concentrated on a small area (high current density). Also, large cathodes may not be easily polarized, thus maintaining a relatively high corrosion rate.