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The Difference Between Primary and Secondary Battery Chemistry


Batteries come in various shapes and sizes. From the very popular lithium batteries to the eco-friendly alkaline models, through carbon zinc, silver oxide, and zinc air models. But regardless of the voltage, energy density, or size, all batteries are categorized as either primary or secondary batteries, based on the battery chemistry​​. 

As a seller, it’s important to know the difference between primary and secondary battery chemistries. This knowledge gives you an edge in the market, especially if you sell battery-powered electronic products. So read on to get a breakdown of the key differences so that you can be sure to stock the solutions your buyers need! 

Table of Contents
The mechanics of a battery
What is a primary battery?
Common examples of primary batteries
What is a secondary battery?
Common examples of secondary batteries
Differences between primary and secondary batteries
Some basic applications of primary and secondary batteries

The mechanics of a battery

Closeup battery setups

Before anything, it’s important to understand how a battery works. A battery can be considered a miniature chemical factory that converts its chemical energy into electrical energy. 

The battery comprises two distinct parts: a cathode and an anode. The cathode refers to the positive end of the battery while the anode is the negative end.

Now, when a battery is inserted into a device such as a flashlight or a phone, the chemical reaction within it is triggered. This results in the flow of electrons, which is the electrical current we use to power our devices.

At the cathode, certain chemicals seek to shed their electrons, whereas, at the anode, certain chemicals want to receive them. When the two ends of the battery are connected with a wire, the electrons travel from the anode to the cathode, generating an electric current along the way.

The chemicals within the battery can only produce electricity for a limited time, as they are consumed during the reaction that produces electricity. Eventually, the battery will run out of power.

This is why rechargeable batteries are necessary for devices such as phones and laptops. When these batteries are plugged in, they undergo a reverse chemical reaction that restores the battery’s chemical energy, effectively returning the electrons to their original positions to produce electricity again the next time you need them.

What is a primary battery?

Simply put, primary batteries are disposable batteries. These batteries are non-rechargeable, no thanks to their chemistry. In a primary battery (AKA primary cell), the action of the chemicals producing the electricity is non-reversible. This means that when the active electrochemical of both the cathode and anode are exhausted, the battery becomes useless.

Common examples of primary batteries

  • Zinc carbon batteries: These batteries were first created in the 1870s and quickly became commercially available in the 1900s. Here’s an overview of the zinc-carbon battery chemistry: it features an ammonium chloride electrolyte conducted by manganese iv oxide and zinc electrodes. 

In the more powerful zinc carbon batteries, carbon (in the form of graphite) is always added to the cathode to make it more conductive. These batteries are cheap but great for applications requiring small power draws.

  • Alkaline batteries: Also known as zinc-manganese iv oxide alkaline batteries, alkaline batteries are upgraded carbon batteries. The only difference between alkaline battery chemistry and zinc carbon battery chemistry is in their respective electrolytes. 

Instead of ammonium chloride, alkaline batteries use potassium hydroxide as an electrolyte. Since ammonium chloride makes the zinc electrode rust easily, while potassium hydroxide electrolyte batteries do not, alkaline batteries have longer shelf lives.

  •  Lithium-based primary batteries: Now, lithium batteries are commonly secondary batteries. However, for the sake of appliances and devices requiring primary batteries with high energy density (e.g pacemakers), lithium-based primary batteries are used too. 

These batteries can churn out massive voltage over an extended timeframe. The lithium battery chemistry will be explained shortly under secondary batteries.

What is a secondary battery?

Imagine having a phone that you could never recharge once the battery ran out. Sounds frustrating, right? Well, luckily we have secondary batteries to save the day!  A secondary battery, also known as a rechargeable battery, is a type of battery that can be charged and discharged multiple times.

The beauty of secondary batteries lies in their ability to store and release energy over and over again. This makes them a cost-effective and eco-friendly alternative to primary batteries. Instead of constantly buying new batteries and adding to the waste in landfills, we can simply recharge our secondary batteries and use them again and again.

Common examples of secondary batteries

  • Lithium-ion batteries: These are likely the most widely used batteries for laptops, mobile phones, and a wide range of other mobile technologies. Lithium-ion batteries are fast-charging batteries with high capacity for energy storage, and they are lightweight. So, what’s not to love? 
  • Nickel-cadmium batteries: These batteries are highly durable and possess the ability to preserve power longer. However, they can cause high voltage when not used properly. The chemistry of nickel-cadmium batteries is such that active compounds are transferred between nickel and cadmium electrodes.
  • Lead acid gel batteries: Recognized as some of the oldest batteries, lead acid gel batteries are put to good use in RV cycles, wheelchairs, and whatnot. These batteries are a reliable source of power but have a track record of causing malfunctioning in devices when charged wrongly. In lead acid battery chemistry, the electrolyte is a gel of fumed acid and sulfuric acid. Hence, the name.

Differences between primary and secondary batteries

Primary batteries Secondary batteries
Shorter shelf life Longer shelf life
Disposable and used once Rechargeable and used multiple times
Typically light and portable Often heavy and bulky
Cheap but with continuous replacement costs High initial costs but cost-effective at the long-run
Used for light-duty applications Built for heavy-duty applications
High internal resistance Low internal resistance
Dry cell Wet cell
Easy to use Difficult to handle

Some basic applications of primary and secondary batteries

  • Primary batteries: They are often used in moderate to low power-consuming applications that draw occasional power. Some such applications include cameras, robot toys, watches, lights, and radios.
  • Secondary batteries: They are more popular in the industrial sector and are, therefore, often termed industrial batteries. You’ll often find secondary batteries in industrial handling vehicles, military equipment, automotive, electric bicycles, and golf carts.


Keeping yourself updated about the products you sell is important to ensure you have a better understanding of your market and audience. This post highlighted the key differences between primary and secondary battery chemistry. You can also check out this post on how to check and test car batteries.

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