Lithium ion Battery

What is a Lithium ion Battery?

A lithium ion battery is the one which gets electrons flowing into the battery by the element named Lithium, or li as the chemical symbol. Each battery has a positive and negative terminal from which the electrons flow in order to power up the device. Lithium ion batteries invented back in 1991 are today the most popular due to their distinguishing features. These batteries are considered the future of batteries and may even start to overshadow the gasoline-powered technologies. Lithium ion batteries provide a much higher energy density than any other comparable battery technologies but are highly inferior to gasoline’s energy density. The storage medium is the one which affects the energy density in a lithium ion battery. The scientists are trying to replace the storage medium (graphite to silicon) which will be able to multiply the energy density by 4.4x.

lithium ion batteries

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How a Lithium ion battery works:

This type of battery has taken over the world. Be it DSLR cameras, car batteries or portable mobile phones, most devices today are embedded with lithium ion batteries. To explain the working of a lithium ion battery, we shall take an example of a lithium ion cell used in a DSLR camera. The cell is made up of various sheets through which the electrons flow when a load is connected with the cell. These electrons start to flow automatically as if they were present on the sheets in an unstable condition, before the load was connected. These unstable electrons are stored in the cell in a container called as graphite, with a higher electrochemical potential. Before these are stored, they must be separated from the atomic structure of an element. 

Lithium is an element which has a high tendency to lose an electron from its outer shell which makes it very reactive to nature but lithium atoms such as lithium oxides are very stable. The basic working of a lithium ion cell can be understood by considering an external power source, the positive side of which will attract the electrons. The middleware of an electrolyte is used to make sure the flow is direct and no electron is blocked. In a continuous flow through the external circuit, the electrons reach the positive end and get trapped between the graphite layers. In the same way, the positive side attracts the lithium ions which also results in getting them trapped in between the graphite layers, these get stored with a high electrochemical potential. 

As soon as this cell is connected to a load, all the electrons trapped in graphite are released and start to flow through the load and provide electricity for us. Today almost all of the batteries use the same process of electricity disposal. 

lithium ion battery

Why are lithium batteries so popular? 

The three characteristics for a good energy source are low cost, high energy density and longer life. The lithium ion grants these three characteristics and fares well. 

Cost of Lithium ion battery:  Considering the cost factor of a capital cost to set up a lithium ion battery is much higher than its counterparts but if the running cost is compared between electric and gasoline cars, the electric cars tend to consume 1/3 of the price of the gasoline cars. The reason for the high capital cost is the presence of nickel, cobalt and metal oxide components. The manufacturers produce much higher quantities of nickel and cobalt due to which the price of lithium ion batteries are six times than that of lead acid one and three times than that of a nickel metal hydride battery. However, the cost of a lithium ion battery as per kilowatt hour has been seen to be dropping at a great rate over the last few years which may make it possible for the lithium ion battery to overcome the capital cost hurdle.

Longevity of Lithium ion batteries: Old Lithium ion batteries used to die in a single year compared to modern laptop batteries which take 3-4 years to die. A lithium ion battery dies slowly even if not in use, meaning it does not require any electron flow to erode. As per the processing discussed above, when the electrons flow through the load they are covered with a coating called solvent molecule. When the first charge happens, the lithium ions react with the solvent molecules to form an SEI layer which allows the lithium ions to pass through it. When Lithium ion is charged for some time and power supply is removed, the lithium ion acts as an open circuit. The second SEI layer, much thicker, is created when solvent molecules react again. Similarly, the degradation process of a lithium ion battery is a slow process when there is an open circuit. The more the ions are charged, the more they react and thicken the SEI layer, accelerating the degrading process of the lithium ion battery cell. The longevity of the battery is both saved and deteriorated by the SEI layer. 

NOTE: To enhance the life of a battery, an electrolyte such as Vinylene carbonate is added. As to why current TESLA batteries last for about 3,000 cycles or seven years. This is in process to enhance it further to 10,000 cycles (25 years of battery life). 

Today, almost all of the electronic gadgets, be it handheld or desktop operated are being embedded with lithium ion batteries, but the only difference is the composition of the metal oxides used. This is due to the carrying cost, energy density and life span depends on the type of use and application in which the battery is being used. These stats have cleared how the lithium ion batteries are enhancing their pros and getting better day by day by increasing their life and decreasing their cost. Aqueous lithium ion battery with the addition of helper halogenation increases the mobility of the lithium ion battery and decreases the flammability of the battery. Furthermore, these batteries need to be more cost, life and energy efficient in order to be the safest go-to batteries for the automobile industry specifically.

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