Week 1 Understanding Different Battery Chemistry

AIM:

1.Prepare a table which includes materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium ion cells.Give your detailed explanation on it

Solution:

BATTERY: Battery is a device that is able to store electrical energy in the form of chemical energy, and convert that energy into electricity.

There are two main categories of lithium ion batteries: primary (single-use) and secondary (rechargeable).

Imporatant Point:

• Lithium ion batteries are batteries that function based on the transfer of lithium ions between a cathode and an anode.
• Lithium ion batteries have higher specific energies than batteries made from other materials such as zinc and lead due to the relatively light weight and low density of lithium.
• Lithium batteries are also more stable over charge/recharge cycles due to the small radii of lithium ions, which causes fewer disruptions of the electrode
• structure during ion transfer. Lithium ion batteries commonly use graphite and cobalt oxide as additional electrode materials.
• Lithium ion batteries work by using the transfer of lithium ions and electrons from the anode to the cathode. At the anode, neutral lithium is oxidized and converted to Li+.These Li+ ions then migrate to the cathode, where they are incorporated into LiCoO2.This results in the reduction of Co(IV) to Co(III) when the electrons from the anode reaction are received at the cathode. Because lithium is involved in the reactions at both electrodes, the battery can be recharged by running the reactions in reverse.

Material of Anode and Cathode:

1.Lithium Cobalt Oxide (LCO): Lithium Cobalt Oxide (LiCoO2) is a mature battery technology, characterized by a long cycle life and high energy densities. The cathode consists of a cobalt oxide and anode is of graphite carbon. The cathode has a layered structure and during discharge, lithium ions move from the anode to the cathode. The flow reverses on charge. The drawback of Li-cobalt is a relatively short life span, low thermal stability and limited load capabilities (specific power).

• Material for cathode and Anode:The cathode consists of a cobalt oxide and anode is of graphite carbon.

2.Lithium Manganese (LMO): Lithium Manganese (LiMn2O4) battery cell's cathode is made out of lithium manganese oxide. It forms a three-dimensional spinel structure which improves ion flow on the electrode, which results in lower internal resistance and improved current handling, in comparsion with Cobalt based batteries. This three dimensional spinel architecture also exhibits high thermal stability and enhanced safety, but at the cost of cycle, calendar life, and energy density. Pure Li-manganese batteries are no longer commonly, they may only be used for special applications. Recent trends indicate that most Li-manganese batteries are blended with lithium nickel manganese cobalt oxide (NMC) to improve the specific energy and prolong the life span, and is popular in most Electric Vehicles.

• Material for cathode and Anode:Its anode material is LiaC6, the cathode material is LibMn2O4

3.Lithium Nickel Cobalt Aluminum Oxide (NCA): Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2) cathode material is highly thermally stable cathode material, doping the lithium nickel cobalt oxide with aluminum both stabilizes its thermal and charge transfer resistance. NCA shares similarities with NMC in offering high specific energy, reasonably good specific power and a long life span.

High energy and power densities, as well as good life span, make NCA a candidate for EV powertrains.

• Material for cathode and Anode:Its anode material is LiaC6, the cathode material is LibNi0.8Co0.15Al0.05O2 and the carrier is Li+.

4.Lithium Nickel Manganese Cobalt oxide (NMC): Lithium Nickel Cobalt Manganese (Li(NiCoMn)O2) batteries are made of cathode materials which is combination of nickel, manganese and cobalt, typically one-third nickel, one-third manganese and one-third cobalt, also known as 1-1-1. Similar to Li-manganese, NMC can be tailored to serve as Energy Cells or Power Cells, like other lithium-ion battery varieties, NMC batteries can have either a high specific energy density or a high specific power. They however cannot have both properties in the same pack. For example, NMC in an 18650 cell for moderate load condition has a capacity of about 2,800mAh andcan deliver 4A to 5A. NMC in the same cell size can be optimized for specific power with capacity of about 2000mAh, but capable of delivering a continuous discharge current of 20A.

• Material for cathode and Anode: The anodes in all various technologies of lithium ion are all made from graphite. The differences are the cathode which contains changing cobalt, nickel or manganese concentrations.

5.Lihium Ion Phosphate (LFP): In Lithium Iron Phosphate (LiFePO4) Batteries phosphate is used as cathode material, Li-phosphate offers good electrochemical performance with low resistance. This nano-scale phosphate material for cathode in Lithium Ion batteries is most viable option because of its low cost,environmental friendliness, long cycle and calendar lives (chemical stability) and good capacity (170 mAh/g). Doping with transition metals results in reduction of internal impedance. LiFePO4 batteries are incombustible in case of misuse during charging or discharging, they are more stable during overcharge or short circuit conditions and they can withstand high temperatures without decomposing. LFP is more tolerant to full charge conditions and is compartively less vunerable to stress even if kept at high voltage for a prolonged time.

• Material for cathode and Anode: Its anode material is LiaC6, the cathode material is LibFePO4

6.Lithium Titanate (LTO): Lithium Titanate ((Li2TiO3)) battery is a modified Li Ion battery in which the graphite in the anode is replaced by Li-titanate which forms a spinel structure. The cathode can be lithium manganese oxide orNMC or LFP, or other lithium battery Chemistry. LTO has a nominal cell voltage of 2.40V, can be fast charged and can deliver a high discharge current of 10C. Even the cycle life is higher than regular Li-ion batteries. LTO exhibits excellent low-temperature discharge characteristics (capacity of 80 percent at –30°C). Thermal stability under high temperature is comparitively better, highly tolerant to operational abuses and can comfortably perform up to 55 °C and can go up to 65 °C.

OTHER INFORMATION:

Table 1: The key properties and Cost comparison of the lithium-ion batteries

Battery type	Energy Density	Life span	Cost
LMO	Medium	Low	Low
NMC	High	High	High
NCA	High	Medium	High
LFP	Low	High	Low
LTO	Very Low	Very High	Very High

2.Compare the differences between each type of Li+ion batteries based on their characteristics.

Solution:

Lithium-ion battery Types	specific power	specific energy	safety	lifespan	cost	performance
Lithium Cobalt Oxide	low	high	low	low	low	moderate
Lithium Manganese Oxide	moderate	moderate	moderate	low	low	low
Lithium Nickel Manganese Cobalt Oxide	moderate	high	moderate	moderate	low	moderate
Lithium Iron Phosphate	high	low	high	high	low	moderate
Lithium Nickel Cobalt Aluminum Oxide	moderate	high	low	moderate	moderate	moderate
Lithium Titanate	moderate	low	high	high	high	high

• Lithium Cobalt Oxide has high specific energy as compared to the other batteries which make it the preferred choice for laptops and mobile phones. It also has a low cost and a moderate performance. However, it is highly unfavorable in all the other aspects when compared to the other lithium-ion batteries. It has low specific power, low safety, and a low lifespan.
• Lithium Manganese Oxide has moderate specific power, moderate specific energy, and a moderate level of safety when compared to the other types of lithium-ion batteries. It has the added advantage of a low cost. The downsides are its low performance and low lifespan. It is usually used in medical devices and power tools.
• Lithium Nickel Manganese Cobalt Oxide has two major advantages as compared to the other batteries. The first one is its high specific energy which makes it desirable in electric powertrains, electric vehicles, and electric bikes. The other is its low cost. It is moderate in terms of specific power, safety, lifespan, and performance when compared to the other lithium-ion batteries. It can be optimized to either have high specific power or high specific energy.
• Lithium Nickel Cobalt Aluminum Oxide offers one strong advantage as compared to the five other batteries and that is high specific energy. It is pretty moderate in the rest of the characteristics like performance, cost, specific power, and lifespan. The only downside to this battery type is its low level of safety. Its high specific energy and moderate lifespan make it a good candidate for electric powertrains.
• Lithium Iron Phosphate only has one major disadvantage when compared to other types of lithium-ion batteries and that is its low specific energy. Other than that, it has moderate to high ratings in all the other characteristics. It has high specific power, offers a high level of safety, has a high lifespan, and comes at a low cost. The performance of this battery is also moderate. It is often employed in electric motorcycles and other applications that require a long lifespan and a high level of safety.
• Lithium Titanate offers high safety, high performance, and a high lifespan which are very important features every battery should have. Its specific energy is low compared to the five other lithium-ion batteries but it compensates for this with moderate specific power. The only major disadvantage of lithium titanate as compared to the other lithium-ion batteries is its extremely high cost. Another important feature of this battery worthy of mention is its remarkably fast recharge time. It can be used for storing solar energy and creating smart grids.