There are so many types of batteries today that it’s hard to keep track of them all. Gone are the days of the simple, disposable alkaline AA battery. Instead, we live in a world of batteries with exotic metals like cadmium, zinc, and even lithium. And of the battery types out there, lithium always seems to get the most attention.
But what is a lithium battery, and how does it work? This article walks you through all the basics you need to know about lithium batteries.
What is a Lithium Battery?
A lithium battery, also known as a lithium-ion or Li-ion battery, is a particular type of battery that uses chemical reactions from lithium, a metal, to generate electrical power. Unlike conventional alkaline batteries, lithium batteries can be recharged many times. This makes lithium batteries useful for a variety of consumer and industrial applications such as electric vehicles (EVs), hybrid vehicles, and electronics.
How Does a Lithium Battery Work?
Before getting into how lithium batteries work, it’s important to go over a few technical terms:
- Anode: the positively charged part of a battery that electrons move from. Lithium battery anodes are made of graphite, an unreactive material made of very thin layers that can easily store lithium atoms
- Cathode: the negatively charged part of a battery that electrons move toward. Lithium battery cathodes are made of lithium metal oxides.
- Separator: a porous boundary in a lithium battery that separates the cathode from the anode and allows only lithium ions to pass through. Free electrons cannot move through the separator.
- Electrolyte: a special liquid solution in the lithium battery that allows lithium ions and electrons to easily move
Lithium: An Unstable Atom That Craves Structure
There are also two things to know about lithium. First, the atom is highly unstable and will easily shed an electron to form a lithium ion (Li+) and a free electron. This is why lithium is such a reactive metal.
The second thing to know is that lithium can be quite stable when structured within a metal oxide. This is why lithium batteries incorporate metals like lithium cobalt oxide and lithium nickel manganese cobalt oxide (more details on these below).
Step 1: Steady (Discharged) State
The natural tendency for lithium atoms is to form part of a metal oxide in the positively charged cathode. When this is the case in a lithium battery, then the battery is fully discharged and cannot provide any more power.
Step 2: Moving Electrons to Recharge the Battery
To recharge a lithium battery, it’s first connected to a power source, which attracts and moves electrons from lithium atoms to the other side of the battery, or anode. As more electrons gather in the anode, positively charged lithium ions in the cathode move across the separator to the negatively charged anode.
Once enough electrons have been moved to the anode (along with corresponding lithium ions), the battery is charged. Keep in mind that electrons cannot move across the separator, which is why electrons simply don’t rush to the positively charged cathode after removing the charger. Until someone connects the battery terminals, the lithium atoms will stay stored within the many layers of the graphite sheets.
Step 3: Using the Battery
When someone connects a load to the lithium battery, two things happen. First, lithium atoms tend to move back toward the metal oxide by passing through the separator. When this happens, electrons in the anode also move toward the positively charged anode. Again, since electrodes can’t move through the separator, their only path is along the circuit created by connecting the load to the battery. This is how lithium batteries generate electrical power.
Step 4: Back to Steady (Discharged) State
As lithium ions and electrons move from the graphite anode to the metal oxide anode, the lithium atoms reach a stable form within the metal oxide. When all the lithium has moved back to the metal oxide, the battery is spent and will need to be recharged.
Why Are Lithium Batteries So Popular?
Despite occasionally negative media about the dangers of lithium batteries, there’s a lot of attention on research and development to improve battery technology. The reason is that, compared to other rechargeable batteries, lithium batteries have a lot of advantages.
Advantages of Lithium Batteries
- High energy density: lithium batteries can store more energy than a similarly sized lead acid battery
- Low weight: lithium batteries are more practical for applications where weight is important, such as portable electronics
- Long life: No battery can last forever, but lithium batteries have a much longer life compared to lead acid or nickel cadmium batteries
- Consistent power: Unlike lead-acid batteries, lithium batteries don’t experience a drop in voltage as the battery discharges
- Fast charging: Lithium batteries can charge faster compared to lead acid batteries. And, unlike nickel-cadmium batteries, lithium batteries don’t need to be fully discharged before they can be recharged again
Why Do Lithium Batteries Die?
Despite the many advantages of lithium batteries, the fact is that they degrade over time, leading to more frequent charging and worse performance.
Keep in mind that lithium batteries work because lithium ions are moving from one side of the battery to another. Ideally, all the lithium ions in the anode will move to the metal oxide cathode so that the battery can be fully recharged. But occasionally, lithium ions bind with other molecules in the battery to form compounds that are stable enough to keep the lithium from “freeing” itself when the battery is recharged. This is what eventually reduces the maximum capacity of a lithium battery over time.
Another factor is heat. When exposed to high temperatures, the electrolyte in the lithium battery will break down, affecting the ability of lithium ions to travel back and forth across the separator.
The good news is that it’s possible to restore and reuse components in a lithium battery by recycling it.
Are Lithium Batteries Recyclable?
Yes, lithium batteries are recyclable. In fact, most places require everyone — businesses and individuals alike — to properly dispose of lithium batteries, which are still quite reactive even when depleted.
What Parts of Lithium Batteries Are Recycled?
Just about every material in a lithium battery is recyclable. That includes:
- The graphite in the anode
- The metal oxides in the cathode
- Copper and aluminum conductive material
- Separator plastics
During the recycling process, parts of the lithium battery are separated and crushed or smelted. These components can then be processed to create recycled lithium batteries that can work just as well as new ones. Keep in mind that these components and chemistries have high value, which is why battery recyclers are willing to pay market prices for used batteries.
How Do You Recycle Lithium Batteries?
It can be challenging to responsibly recycle your batteries, but there are specialized battery recycling companies that can provide white-glove service so that you can focus on more important things.
When you work with Battery Recyclers of America, we take care of everything, from pick-up at your location to issuing an EPA recycling certificate. We’ll even pay you competitive market prices for your batteries. All it takes is 30 seconds to get started with a quote for full-service battery recycling.
