Carbon-zinc Batteries: A Classic But Fading Power Source

Carbon-zinc batteries: a classic but fading power source

In our daily lives, carbon batteries—a type of inexpensive battery—can often be found in many small household appliances such as remote controls, clocks, and simple toys. As one of the "pioneers" of dry-cell batteries, they were once ubiquitous in every corner of life. However, with technological advancements, they are gradually being replaced by alkaline batteries with superior performance. So, what exactly are carbon batteries? What are their characteristics, and in what scenarios are they suitable?

1. What is a carbon-zinc battery?

Carbon zinc batteries, also known as "zinc-manganese dry cells," have a cathode primarily composed of manganese dioxide, an anode made of a zinc can, and an electrolyte consisting of an aqueous solution of ammonium chloride or zinc chloride. Due to the main conductive material in the cathode being derived from carbon rods, they are commonly referred to as "carbon batteries.".

In appearance, carbon zinc batteries are very similar to common alkaline batteries, with specifications such as AA (No. 5) and AAA (No. 7). However, upon closer inspection of the labels, you will often find terms like "Super Heavy Duty" or "Carbon Zinc Battery," which are the most straightforward ways to identify them.

II. Introduction to Working Principles

The discharge of a carbon-zinc battery is an electrochemical process:

At the negative electrode, zinc reacts with the electrolyte, losing electrons and forming zinc ions.

Electrons flow from the negative terminal to the positive carbon rod through the external circuit (connected devices), forming an electric current.

At the cathode, manganese dioxide gains electrons and is reduced.

The entire reaction process continues until the zinc can is corroded through or the chemicals are depleted, at which point the battery is depleted.