Week 1 Understanding Different Battery Chemistry
1. Solution:-
Introduction:-
A battery is made up of an anode, cathode, separator, electrolyte, and two current collectors (positive and negative). The anode and cathode store the lithium. The electrolyte carries positively charged lithium ions from the anode to the cathode and vice versa through the separator. The movement of the lithium ions creates free electrons in the anode which creates a charge at the positive current collector. The electrical current then flows from the current collector through a device being powered (cell phone, computer, etc.) to the negative current collector, The separator blocks the flow of electrons inside the battery.
CHARGE/DISCHARGE
While the battery is discharging and providing an electric current, the anode releases lithium ions to the cathode, generating a flow of electrons from one side to the other, When plugging in the device, the opposite happens, Lithium ions are released by the cathode and received by the anode.
Working:
Instead of Oxidation and reduction, transport pf Li^+ ions from one electrode to another electrode through electrolyte by the transport of electrons through external circuit
The LiCoO_2 is coated with aluminium current collector and the graphite is coated with copper current collector to ease the flow of electrons.
The separator only allows the lithium ions to pass through it, but doesn't allows electrons to pass. The electrons then moves through the external circuit and travel back to the lithium ions from which its was separated. The separator in the lithium-ion cell is to electrically isolate the positive and negative electrodes to avoid self-discharge of the cell and short circuit. The separator is often made from fibre, glass mat or polymer
While the battery is discharging and providing an electric current, the anode releases lithium ions to the cathode, generating a flow of electrons from one side to the other. When plugging in the device, the opposite happens.
Types of L-ion batteries:
1. LCO: LCO stands for Uthlum cobalt battery. Lithium cobalt oxide is one of the most common Lithium-lons, It has a chemical symbol which is LiCoO2, and is abbreviated as LCO. For simplification, Li-cobalt-which is the short term-can also be used for this type of battery. Cobalt is the core active material that defines the character of the battery.
LCO batteries technology and applications
LCO (Lithium cobalt oxide) was invented in the year 1991. Its anode material is Liace, the cathode material is LibCoO2 and the carrier is Li+. It is used in various applications ranging from electronic devices to all laptops and phone batteries. The majority of lithium-ion batteries for portable devices are cobalt-based. The system contains a cobalt oxide cathode (positive electrode) and graphite carbon anode (negative electrode).
2.LMO: LMO stands for Lithium manganese oxide batteries, which are commonly referred to as lithium-ion manganese batteries or manganese spinel. This battery was discovered in the 1980s, yet the first commercial lithium-ion battery made with a cathode material made from lithium manganese was produced in 1996.
LMO batteries technology and applications
3.LMO (Lithium magnesium oxide) was Invented in the year 1996. Its anode material is Llace, the cathode material is LibMn204 and the carrier is Li+. It is used in different applications like power tools and electric cars. LMO batteries have the ability to deliver a lot of
energy in a short period of time, which makes them extremely useful for use in power tools like drills. In 1996, lithium manganese oxide was first used as a cathode material. A three-dimensional spinel structure was formed by this structure, this improves the flow of ions between the electrodes. The high flow decreases the Internal resistance and increases loading capability. LMO batteries are usually used in medical devices and equipment, power tools, electric bikes, and more. Because of their thermal resistance and higher safety. LMO batteries can also be used for laptops and electric cars.
4.NMC: NMC stands for Lithium Nickel Manganese Cobalt Oxide battery. (LINIMnCoO2) The cathode combination of NMC (nickel manganese-cobalt) is among the most successful Li-ion systems. The NMC systems can serve as a Power Cell or an Energy Cell
NMC batteries technology and applications
NMC (Nickel Manganese Cobalt Oxide) battery was invented in the year 2008. Its anode material is LiaC6, the cathode material is LibNil-x-yCoxMny02, and the carrier is Ll+. They commonly use it in different applications like Energy Systems and electric cars. NMC combines the best of nickel and manganese. Nickel has high specific energy but poor stability, manganese can form a spinel structure so as to achieve low internal resistance yet provides low specific energy. Joining the metals increases the strengths of both parts. NMC batteries are widely used for power tools, energy storage systems (EES) which need frequent cycling, and electrical power trains like automotives. The cathode combination typically used is 1-1-1 which means one-third nickel, one-third manganese, and one-third cobalt. This reduces the raw material cost due to lowered content of cobalt. Another known combination for NCM is 5-3-2 (5 parts nickel 3 parts cobalt, and 2 parts manganese). Other combinations are also possible.
5. LFP: LFP batteries stand for Lithium Iron phosphate (UFOPO) batteries, which are known as Il-phosphate batteries as well. They use phosphate as cathode material. In addition, they benefit from the low resistance properties that enhance their thermal stability and safety.
LFP batteries technology and applications
LFP (Lithium Iron phosphate) was invented in the year 1996. Its anode material is LiaC6, the cathode material is LibFePO4 and the comer is Li+. They use LFP batteries in different applications like electric cars, electric buses, and electric trucks. The LFP is ideal for use in electric trucks or buses-as volume or weight isn't really a restriction as is in cars- because the battery is less energy-dense yet cheaper to manufacture than other Li-ion batteries types. In addition, they use LFP batteries in other applications like electric motorcycles which need a longer life cycle and increased safety. LFP provides good electrochemical performance with lower resistance. This is enabled by the nano-scale phosphate cathode material. The main benefits are long cycle life, higher current rating, and thermal stability which means extra safety.
6.LTO:-
Lithium-titanate-oxide(LTO) battery
The lithium-titanate-oxide (LTO) battery is a type of rechargeable battery which has the advantage of being faster to
charge than other lithium-ion batteries, but the disadvantage of having a much lower energy density.
materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium ion cells.
2.Compare the differences between each type of Li+ion batteries based on their characteristics?
ANSWER:
The difference between lithium and lithium-ion batteries is that one is not rechargeable (primary cell) and the other can be recharged (secondary cell). In addition to this, Lithium batteries have a shelf life up to four times longer than lithium-ion batteries and are also much cheaper and easier to make.
Conversely, the items we rely on to hold their charge for extended periods of time are best powered using Lithium batteries. Whether it's a medical pacemaker or safety features like a smoke alarm, Lithium batteries are preferred as they last for so much longer. And, although we'd like to point out that it's very rare, Lithium-ion batteries have been known to catch fire and explode, a feature we thankfully don't see from Lithium batteries.
Lithium Cobalt Oxide, LCO
The Lithium Cobalt Oxide, UCO02, battery is a type of lithium ion battery that find uses in many consumer items of electronic equipment. It provides a very high level of specific energy density along with a good level of safety.
The battery consists of a cobalt oxide cathode with a layered structure. The anode is graphite (carbon). During the discharge cycle, lithium ions move from the anode to the cathode, and in the reverse direction during charge.
The graphite anode limits the battery life as the solid electrolyte interface changes and also as a result of anode thickening. Newer batteries may incorporate nickel or manganese to improve the lifetime as well as reducing manufacturing costs.
One of the drawbacks of the LCO battery is that its current capability in both charge and discharge is limited. As a guide, it should not be charged or discharged at a greater rate than its capacity, ie a 2400mAh battery should not be charged or discharged with a current greater than 2400mA. Often figures of 0.8 of the charge level are recommended.
The LCO battery is now being supplanted in some applications by Lithium Manganese, as well as NMC and NCA types. This is occurring as a result of the improved performance of these other types as development improves the performance and as a result of cost.
Lithium Iron Phosphate Battery, LFP
The Uthium Iron Phosphate, LFP type of lithium ion battery provides a low internal resistance and high current capability. In order to provide its high of current capability, this type of li-ion battery uses a nano-scale phosphate cathode material.
In terms of performance this type of lithium ion battery provides a slightly lower terminal voltage and it has a slightly higher self discharge rate than other forms. However against this it provides a high current rating, and good thermal stability combined with a good level of, and good thermal stability.
Lithium Manganese Oxide, LMO
This type of lithium ion battery uses Lithium Manganese Oxide, LiMn204 as its cathode material. This type of lithium ion battery is structured to allow high currents to flow and this enables it to provide very high current levels and also to be fast charged as well.
It generally uses a three-dimensional spinel structure, ie, one in which the crystal structure in the cubic, isometric, system, with the oxide anions arranged in a cubic close-packed lattice. This structure improves the flow of ions on the electrode, thereby increasing he current capability and lowering the Internal resistance of the cell. A typical 1500mAh battery may be able to deliver steady currents of up to 20 A, obviously for a relatively short time because of the overall battery capacity.
The structure of this type of lithium ion battery also has the advantage that it improves the thermal stability and improves the safety of the cell.
However the disadvantage of the cell is the limited number of charge discharge / cycles as well as the limited calendar life, Le. the degradation over time since manufacture.
Lithium Nickel Cobalt Aluminium Oxide, NCA
The Lithium Nickel Cobalt Aluminium Oxide battery, or NCA, is a li-ion battery type that is rarely seen in consumer applications but is being investigated for the automotive industry. Its main advantage is that it has a good life span and high energy and power density figures.
However these features come at a cost and in view of the safety elements, it must be used with care. Further development is also required to bring it to a state where this type of li-ion battery can be more widely used.
Lithium Nickel Manganese Cobalt Oxide, NMC
The lithium nickel manganese cobalt oxide lithium battery type uses a cathode comprising of a combination of nickel, manganese, and cobalt.
The key to this lithium ion battery type is the combination of nickel and manganese. Nickel is known for its high specific energy, but poor stability whereas manganese provides low internal resistance but at the cost of low specific energy. Combining both in a cell in the correct manner is able to provide the required balance of the properties of both metals.
The cathode combination often consists of a combination of nickel, manganese and cobalt in equal proportions in a combination known as 1-1-1. This combination reduces cost by reducing the cobalt content, whilst still retaining some of the key performance parameters.
Another popular combination consists of 5 parts nickel, 3 parts cobalt & 2 parts manganese (5-3-2).
The NMC type of lithium ion battery can be optimised for either to high specific power or high specific energy. With the high cost of cobalt, manufacturers are trying to move away from its use, often increasing the use of nickel, so this is often a major fact in the choice of composition of the battery.
These types of lithium ion battery are some of the more popular ones available. However as the technology is continually seeing more development, new lithium ion technologies are always being developed and those which exist are being developed. This has arisen from the needs of the equipment manufacturers. Battery technology in general is forcing development forwards and significant amounts are being invested. As a result, this is a particularly fast moving area of technology where improvements dre always being seen.
