Week 1 Understanding Different Battery Chemistry

AIM:
1. To prepare repare a table that includes materials & chemical reactions occurring at theanode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium-ion cells. Give yourdetailed explanation on it.
2. Compare the differences between each type of Li-ion battery based on theircharacteristics.

INTRODUCTION:
Lithium-ion Cells are a secondary type of battery cell that is they are rechargeable andalso they are reusable which makes them ideally suited for automotive applications andcertain consumer electronics When two or more cells connected they are referred to asbatteries Like other batteries Lithium-ion batteries also rely on the chemical energy storedin the bonds and atoms of elements and compounds and utilize this energy in a chemicalreaction occurring inside the cell. The chemical energy from this reaction is converted toelectrical energy and it is used. Since the Lithium-ion cells are rechargeable, they canperform the reverse reaction using electricity as well.

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.

• Lithium ion batteries can be designed for optimal capacity with the drawback of limited loading, slow charging and reduced longiveity. An industrial battery may have a moderate amphere rating but the focus is on durability. Specific energy only provides part of battery performance.
• Before looking into the materials and chemical reactions of different types of lithium ion batteries. 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 seperator. 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 to the negative current collector. The seperator blocks the flow of electrons inside the battery.

• Electrolyte :
  The electrolyte is an ionic conductor that provides the medium for internal ionicharge transfer between the electrodes • The electrolyte must often comprise a liquidsolvent containing dissolved chemicals the solution that provides the ionic conductivity.
• The Lithium-ion cels use non-aqueous electrolytes.
• Cathode and Anode:
  The Cathode ad Anoide is the two electrodes that are connected by awire in an external circuit The electrons are passing through the external wire and so anelectric current is perorated.The Anode refers to the Electrode through which theconventional current enters into a polarized electrical device.
• The Cathode refers to the electrode through which conventional current leaves anelectrical device.
• Separator:
  The Separator physically isolates the positive and negative electrodes. Theseparator is an ionic conductor but an electronic insulator b. It prevents the internal short-circuiting between the two electrodes.
• Current Collectors:
  The current collectors are the electronic conductors with which theelectrodes are mixed It does not take part in chemical reactions of the cell but instead, iteither allows simple electronic connection to reduce the electronic resistance of anelectrode.

Advantages of Lithium-Ion Battery:

1. it has a high energy density which is two times compare to Ni-Cd.The Lithium-Ion battery is rechargeable.
2. There is no memory effect. Hence it is not needed to discharge them completely before recharging.
3. The battery can handle many charge/discharge cycles.
4. The battery can hold the charge and it can lose only 5% of its charge every month.

Disadvantages of Lithium-Ion Battery:

1. It lasts only two to three years after the manufacturer.
   
2. It is sensitive to high temperatures.
3. If the battery is completely discharged, it can no longer be recharged again.
4. It is relatively expensive.
5. if the "separator" gets damaged, it can burst into flames.

PARTS OF LITHIUM ION BATTERY :

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 will happen that the lithium ions are released by the cathode and received by the anode. The charging and discharging processes are shown.

The 6 commonly used lithium ion batteries are listed below.

• Lithium cobalt oxide (LiCoO2) - LCO.
• Lithium Manganese oxide (LiMn2O4) - LMO.
• Lithium Nickel Manganese cobalt oxide (liNiMnCoO2) - NMC.
• Lithium Iron phosphate (LiFePO4) - LFP.
• Lithium Nickel Cobalt Aluminium Oxide (LiNiCoAlO2) - NCA.
• Lithium Titanate (Li2TiO3) - LTO.

Each Lithium ion batteries provides different characteristics and are used in different applications accordingly.

• Lithium cobalt oxide (LCO) battery was invented in the year 1991. Its anode material is LiaC6, 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).

• Lithium ion manganese oxide battety (LMO) is a lithium ion cell that uses manganese dioxide MnO2 as a cathode material. They function through the same intercalation/ de-intercalation mechanism as other commercilized secondary battery technologies such as LiCoO2. Cathodes based on manganese oxide components are earth - abundant, inexpensive, non - toxic and provide better thermal stability.

MnO2 + Li + +e--->LiMnO4

• Lithium Nickel cobalt aluminium oxides (NCA) battery has been around since 1999 for special applications. It shares similarities with NMC by offering high specific energy, reasonably good specific power and a long life span.

• Lithium Nickel Manganese Cobalt Oxide (NMC) battery offer a combination a nickel, Manganese and cobalt. They are sometimes known as Lithium Manganese Cobalt oxide batteries. NMC batteries have a high specific energy or power.

• Lithium iron phosphate battery (LiFeO4) batteries which is known as Li - phosphate batteries as well. They use phosphate as cathode material. In addition they benefit from the low resistance properties that enchance their thermal stability and safety.

• Lithium Titanate oxide (LTO) batteries is a type of rechargable battery which has the advantage of being faster to charge than other lithium ion batteries but its disadvantage of having a much lower energy density.

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

The Major 6 types of lithium ion batteries was discussed early, Now the major differences in the characteristics can be found when choosing a battery. The major things that can be differenciated from one another.

• Nominal voltage : It is the system voltage at which the device is designed to operate. The rated voltage is usually higher than the nominal voltage to ensure the safe operation of the device.
• Cycle : The charge and discharge when took place for a single time makes a cycle. The higher the cycles can take place, the higher the cycles can takes place then the lifespan is higher.
• Thermal runway : The thermal runway begins when the heat generated within a battery exceeds the amount of heat that is dissipated to its surroundings.Internal battery temperature will continue to rise, causing the battery current to rise creating a domino effect. The rise in temperature in a single battery will begin to affect other batteries nearby and the pattern will continue.
• Specific energy : It is the amount of energy stored per unit mass (Wh/Kg). This is a very important deciding factor that decides how much energy or power from different batteries with the same amount of weight.

Specific energy of different types of lithium based batteries :

The main differences between the lithium ion batteries can be differentiated on the characteristics.

• Nominal Voltage : Most of the batteries are very close when it comes to characteristics. LMO (3.7) has the highest range and LTO (2.4) has the lowest range in volts.
• Cycle life : They differ by a significant amount from each other. LTO battery has the longest life cycle so that it can last longer period of time and it is exactly opposite for the LMO type batteries.
• Charge current rate : Higher the charge current, the less time the battery will take to get fully charged. LTO and LTP are highest NCA comes close to its condenders.
• Discharge current rate : If we need higher discharge rates and faster charging times we should choose a high rated battery instead. LTO has a discharge rate 10 times higher than the others and it t=is one of the safest batteries.
• Thermal runaway : A thermal runaway occurs in situations where an increase in temperature changes the conditions in a way that causes increase in temperature often leading a destructive result. LTO has the highest temperature rating in this and NCA and LCP has its lowest.
• Specific energy : The specific energy density can be calculated by integrating from 0 to t_cutoff. We can obtain the specific energy density in Wh Kg^-1. Lithium ion with cobalt cathodes offer the highest energy densities. This types of applications are cell phones, laptops and digital cameras. Power density indicates how much power a battery can deliver on demand.

For ease of choosing a battery from laymans perspective, the 6 key features are given a value within 0-5 range for all of the, are given with the same parameters which are considered in case of 5 point hexagonal analysis of the batteries. They are

1. Specific energy.
2. Specific power.
3. Safety.
4. Performance.
5. Life span.
6. Cost.

LCO :

Li-cobalt excels on high specific energy but offers only moderate performance specific power, safety and life span.

LMO :

Although moderate in overall performance, newer designs of Li-manganese offer improvements in specific power, safety and life span.

NMC :

NMC has good overall performance and excels on specific energy. This battery is the preferred candidate for the electric vehicle and has the lowest self heating rate.

LFP :

Li-phosphate has excellent safety and long life span but moderate specific energy and elevated self discharge.

NCA :

High energy and power densities as well as a good life span make NCA a candidate for EV powertrains. High cost and marginal safety are negative.

LTO :

Li-titanate excels in safety, low temperature performance and life span. Efforts are being made to improve the specific energy and lower the cost.

• These types of lithium ion batteries are some of the most popular. As technology is continously seeing more development, new lithium technologies are always being developed and those which exists are being developed.
• The figure compares the specific energy of lead-, nickel- and lithium-based systems. While Li-aluminum (NCA) is the clear winner by storing more capacity than other systems, this only applies to specific energy in terms of specific power and thermal stability, Li-manganese (LMO) and Li-phosphate (LFP) are superior, Li-titanate (LTO) may have low capacity but this chemistry outlives most other batteries in terms of de span and also has the best cold temperature performance. Moving towards the electric powertrain safety and the cycle will gain dominance overcapacity (LCO stands for Li-cobalt, the original Li-ion)

CONCLUSION:

• We studied the different batteries by comparing their specific energy,by voltage,power,specific density.

REFERENCES:

• https://batteryuniversity.com/article/understanding-lithium-ion
• https://nickelinstitute.org/blog/2020/february/competitive-technologies-to-high-nickel-lithium-ion-batteries-the-pros-and-cons/