Lithium-Ion Batteries - The Give and Take Behind the Charge

Technology Today

Our world has adapted to technology and its uses more rapidly than at any other time in our history. There are more gadgets and portable electronics at our disposal than ever before. We utilize electronic devices powered by batteries in every part of our lives. Just imagine the areas batteries impact our lives. Lithium-ion battery technology offers high-power density, long life, low self-discharge, low maintenance costs, and low environmental impact.

Lithium-ion batteries most often power electronic devices and other consumer electronics that utilize chargers, such as cell phones, power tools, headphones, smartwatches, tablets, and laptops. In addition, solar energy storage systems, portable power packs, and uninterrupted power supplies also have the rechargeable benefit of these batteries.

The field of medicine also has its share of uses, including medical devices and surgical tools like pacemakers and defibrillators. As you can see, due to their potential for storing large amounts of energy, lithium-ion batteries are used in many applications.

Lithium In Demand

Global lithium demand is estimated to reach 1.79 million metric tons by 2030. Therefore, battery demand growth will be a significant driver of lithium usage in the foreseeable future.

The increased market popularity of rechargeable lithium-ion batteries is mainly due to this battery chemistry's high energy density. Energy density is essential for batteries and refers to the amount of energy stored by a system in a given amount of space. While securing the same amount of energy, lithium-ion batteries can be lighter and thinner than most other types of batteries.

The automotive industry recognizes the high-performance and high-power aspects, and most electric vehicles produced today are powered by lithium-ion batteries, with Tesla being a significant consumer. And the demand for lithium-ion is only going to increase as the electric car market continues to rise in the coming years.

What is A Lithium-Ion Battery?

Lithium-ion batteries or li-ion batteries are a class of rechargeable batteries. Lithium-ions move from a negative electrode to a positive electrode through its electrolyte and separator while discharging and again during charging.

Lithium batteries were developed prior to lithium-ion batteries. However, manufacturers were encouraged to create a rechargeable equivalent because they could not be recharged safely. Thus, Lithium-ion batteries were born. These batteries have a long life and maybe recharged numerous times before degrading.

How Do They Work?

Consider, as an example, smartphones. A chemical reaction happens inside every second you use your smartphone, similar to a baking soda volcano. In addition, the battery has a chemical reaction that is continuously running, and without it, your phone would not be able to function or even turn on.

There are a positive terminal and a negative terminal in all batteries. So electrical energy is, essentially, a flow of electrons from one terminal to the other. In our smartphone, negatively charged electrons flow from the negative terminal, run things like the speakers or the display, and end up in the positive terminal.

Does my Phone Have Electrons in it?

Yes, at least the materials in the batteries do. But where do these electrons originate? In a lithium-ion battery, the electrons come from the element lithium located at the negative terminal called the anode.

Graphite makes up anode material, along with a copper foil coating. Lithium gets stored between layers of carbon graphite, like the graphite in your pencil. The graphite functions as a stable storage space for the lithium atom. Graphite has a crystal structure of layered planes, where the lithium is stored

One inherent property of lithium is that it doesn't like its outermost electron and wants to give it up. This is vital as this process would not happen without its desire to lose an electron.

An atom that has given or taken an electron is called an ion. This makes the atom charged. And the movement of these charged ions is called ionic activity. This activity occurs when a path from the negative terminal to the positive terminal becomes available.

The lithium-ion is now heading to the positive terminal, called the cathode. The cathode material is cobalt, and a conductive aluminum-copper layer is next to the cobalt. The aluminum and copper used also help with electrical conductivity. The cobalt has lost some electrons to oxygen, making it positively charged and seeking the electron that lithium has given up.

Electrons begin to flow when our smartphones' negative and positive terminals are connected. The lithium wants to give up an electron, and the cobalt seeks to gain an electron. When this happens, the electrons move through the circuits and components of your smartphone, providing power.

Houston, We Have A Problem!

But here, we run into a minor issue with the flow of electrons from the negative to the positive terminal. As a result, the cobalt side grows more negatively charged and the other side positively charged.

Electrons want to flow in this fashion, but electrons also don't want to move to an area becoming more and more negatively charged by the second.

To solve this puzzle, we use an electrolyte solution to give the positively charged lithium ions leaving the graphite a way to get to the opposite side via the electrolyte solution. This allows lithium ions to flow to the cobalt side, neutralizing the charge accumulation and maintaining the reaction.

Charge It!

Now let's recharge it. First, we plug in our smartphone, and when we do this, the USB charger applies a higher force on a flow of electrons in the opposite direction. Then electrons are pulled out of the cobalt, thus returning cobalt to its initial state and kicking out the lithium ions.

At the anode side, the electrons are forced back onto the graphite. This action pulls the lithium through the electrolyte and back into the layers of graphite. This is the exact opposite of the earlier reaction, which is why this battery is rechargeable.

The lithium and its electrons move in one direction when you use the phone and, in the opposite when you charge it back up again. These elements love to give and take electrons.

In This Case, it is Better to Give and Receive

This 'giving and taking' or chemical action is intriguing. The science behind it goes back to the early 1970s. However, when looking at this in its entirety, it is a simple chemical reaction that allows the operation of devices we rely on daily. But this simple reaction provides us with a low-cost, fast charging, high-capacity battery. And with years of research, we have now extended battery life, bolstered battery performance, and a great life cycle in our devices. Let's hope those elements keep giving and taking, so we can read articles like this on our tablets and smartphones.

Mar 28th 2022

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