There is no doubt that Lithium-ion batteries have gained huge popularity over recent years. And due to the success of these batteries, people are experimenting with the chemical compositions of the battery to make it futuristic. No matter how advanced chemistry is at the present time, there are still some problems with it. The cost of big batteries is high, the energy density, cycle life, safety.
This article, we are going to study about the Anode materials that are commonly used in Lithium-ion batteries. And we’ll make sure that you have knowledge about the ongoing trends and technology regarding these portable batteries.
What Are Anode Materials For Lithium-Ion Batteries?
The anode materials for Lithium-ion batteries are the ones which can easily evolve oxygen or chlorine gas. The anode is the point where the discharge happens. It is the negative electrode which means the negative half-reaction occurs on this side. The most common material used for the anode is graphite. But gradually, new compounds are also being tested to see if there is an improvement in the electrochemistry of the lithium-ion batteries.
Types Of Anode Materials For Lithium-Ion Batteries:
The various types of anode materials which are commonly used for the lithium-ion batteries are given below. Companies have various options for anodes and they are all used for different purposes.
1: Graphite:
This material is used because it is compact and easily evolves oxygen and chlorine gas. However, graphite is a very brittle compound and needs to be handled delicately. It can easily get damaged which means that the battery will stop working. The graphite used in the Lithium-ion batteries is inert. Still, it has to be taken care of as high current density will affect the oxidation reaction and carbon dioxide will evolve from the battery pack.
The best manufacture of this anode material is Targray. They provide low cost and good energy density. The charging rate of the battery is governed by the sheet of graphene used in the battery. During the charging process, the lithium ions travel to the outer edges of the sheet before intercalation. Still, there is some congestion around the edges as the circuit route is long.
2: Lithium Titanate:
It is intercalation anode material for the Lithium-ion batteries. The material is very similar to graphite but has a stable SEI layer. This material was created or safety purposes. It holds great potential to become a better alternative for graphite. It offers low cost, toxicity, and volume change which makes it better for the battery pack. It is often used for large scale hybrid electrical vehicle due to their increased safety features. Along with this, Lithium Titanate has high power density and long cycle life. The main drawback of this material is the low inherent capacity and electronic conductivity.
Still, the allotropic form of this substance is considered to be one of the most extensive and promising anode materials.
3: Alloying Anode such as Silicon, Tin, and Cobalt Alloy:
Apart from the intercalation process, there are two other mechanisms which are attracted to anodes. It is Alloying and Conversion mechanisms. The alloying mechanism generally includes elements like Silicon, Tin, germanium, phosphorus, etc. These materials have more storage capacity than graphite which is commonly used in Lithium-ion batteries. The best choice is Silicon which has 4200 mAh/g specific capacity which is 11 times more than that of graphite. These materials also have a low delithiation potential which maximizes the discharge voltage in fuel cells.
But the alloy materials share some of the most challenging issues faced by the batteries. The first problem is the expansion and fracture. The large capacity of these materials results in large volume expansion which can cause mechanical failure in the battery. The second issue is with the stability of Solid-Electrolyte Interphase. During lithiation and contraction, an unstable SEI layer is formed between the particles and electrolyte. The third major issue is with the electrode that swells due to volume expansion. It creates a defect in the battery cell design and thus, the scientists have to look for some other anode material which gives better results.
How To Choose Good Anode Materials For Lithium-Ion Batteries?
As you can see, there are serious issues while you are picking the right material for the anode. But there are some basic characteristics that you need to follow. It includes:
· Porosity should be excellent.
· Conductivity should be high.
· Durable and lightweight.
· Low cost.
· The voltage of anode should match with the cathode.
To make sure that the anode of Lithium-ion batteries stays stable, various approaches have been taken. A protective layer is installed in the batteries. At present, various researches have been conducted to test silicon to be a good and effective anode material. Even the Nanotechnology has been integrated with the batteries to check if it is possible to eliminate all the drawbacks of various elements. Yet the SEI layer always appears in the battery. As the layer is composed of electrolyte, it has a risk of carbonate reduction which increases thermal degradation.
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