Week 1 Understanding Different Battery Chemistry

Question 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 (Li-ion) batteries

Lithium-ion (Li-ion) batteries are an important component of energy storage systems used in various applications such as electric vehicles and portable electronics. There are many chemistries of Li-ion battery, but LFP, NMC, LMO, and NCA are four commonly used types.

Lithium Cobalt Oxide ( LCO ):

The Lithium Cobalt Oxide, LiCoO2, 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.

SUMMARY OF LITHIUM COBALT OXIDE BATTERY, LCO
ATTRIBUTE	DETAILS
Key features	High energy density; high level of safety
Main disadvantages	Relatively short life-span; limited high load capability.
Main applications	Consumer electronics:- mobile phones, games, laptops, tablets, e-readers, etc.
Voltage	3.60V nominal with typical operating rate between 3.0 - 4.2 V/cell
Specific energy (capacity)	150 - 200Wh/kg typical
Battery life	500 - 1000 cycles

Lithium Manganese Oxide LMO:

This type of lithium ion battery uses Lithium Manganese Oxide, LiMn2O4 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, i.e. 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.

SUMMARY OF LITHIUM MANGANESE OXIDE, MNO BATTERY
ATTRIBUTE	DETAILS
Key features	High current capability for charge and discharge.
Main disadvantages	Lower energy density than other types of lithium ion battery, low cycle life and calendar life.
Main applications	Power tools, some medical tools some vehicles.
Voltage	~3.70V nominal
Specific energy	100 - 150Wh/kg
Life expectancy	400 - 750 cycles

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.

SUMMARY OF LITHIUM NICKEL COBALT ALUMINIUM OXIDE, NCA
ATTRIBUTE	DETAILS
Key features	High energy density, high power density, good life span.
Main disadvantages	High cost; safety requires more care in the design and use.

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.

SUMMARY OF LITHIUM NICKEL MANGANESE COBALT OXIDE, NMC
ATTRIBUTE	DETAILS
Key features	High specific power or energy.
Main disadvantages	Power / energy density not as high as some other types.
Main applications	Power tools and electric vehicles.
Voltage	3.60 - 3.70 V
Specific energy	160 - 230Wh/kg
Life expectancy	1000 - 2000 cycles.

Lithium Iron Phosphate Battery,( LFP):

The Lithium 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.

SUMMARY OF LITHIUM IRON PHOSPHATE, LFP BATTERY
ATTRIBUTE	DETAILS
Key features	High current capability, longer calendar lifespan.
Main disadvantages	Slightly higher self-discharge rate; low cell voltage (3.3V)
Main applications	Power tools, some medical tools, hobbyist

Lithium titanate (LTO):

Lithium titanate (LTO) anode materials can be used with LMO or NMC cathodes to make a Li-ion cell. LTO cells offers very high cycle life, excellent thermal stability, excellent safety, and good low temperature operation. However, they have much lower energy density than other Li-ion technologies and a low cell voltage of 2.4V.

Material and Chemical Reactions in Different Types of Li-ion cells

Battery Type	Cathode	Anode	Electrolyte	Cathode Reaction	Anode Reaction
Lithium Cobalt Oxide ( LCO )	Lithium Cobalt Oxide(LiCoO2)	Graphite (C6)	Lithium hexafluorophosphate(LiPF6) in Ethylene Carbonate	LiCoO2 + nLi+ +ne- LiCoO2	C6Li 6C + Li+ +e-
Lithium Manganese Oxide LMO	Lithium Manganese Oxide (LiMn2O4)	Graphite (C6)	Lithium hexafluorophosphate(LiPF6) in Ethylene Carbonate	Lim − nMn2O4 + nLi+ + ne− LimMn2O	LinC6 nLi+ + ne−
Lithium Nickel Cobalt Aluminium Oxide (NCA)	Lithium Nickel Cobalt Aluminium Oxide (LiNiCoAlO2)	Graphite (C6)	Lithium hexafluorophosphate(LiPF6) in Ethylene Carbonate	Lim − n(NixCoyAlz)O2 + nLi+ + ne− Lim(NixCoyAlz)O	LinC6 Li0C6 + nLi+ + ne−
Lithium Nickel Manganese Cobalt Oxide (NMC)	Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2)	Graphite (C6)	Lithium hexafluorophosphate(LiPF6) in Ethylene Carbonate	Lim − n(NixMnyCoz)O2 + nLi+ + ne− Lim(NixMnyCoz)O2	LinC6 Li0C6 + nLi+ + ne−
Lithium Iron Phosphate Battery,( LFP)	Lithium Iron Phosphate(LiFePO4)	Graphite (C6)	Lithium hexafluorophosphate(LiPF6) in Ethylene Carbonate	Lim − nFePO4 + nLi+ + ne− LimFePO4	LinC6 Li0C6 + nLi+ + ne−
Lithium titanate (LTO)	Lithium Manganese Oxide (LiMn2O4) and Lithium Nickel Manganese Cobalt (LiNiMnCoO2)	Titanate (Ti5O12)	Lithium hexafluorophosphate(LiPF6) in Ethylene Carbonate	Li(1-n)NiMnCoO2 + nLi+ +ne- LiNiMnCoO2	Li7Ti5O12 Li4Ti5O12 +2Li+ + 3e-

Question2.Compare the differences between each type of Li+ion batteries based on their characteristics

There are different types of lithium-ion batteries and the main difference between them lies in their cathode materials. Different kinds of lithium-ion batteries offer different features, with trade-offs between specific power, specific energy, safety, lifespan, cost, and performance.

The six lithium-ion battery types that we will be comparing are Lithium Cobalt Oxide, Lithium Manganese Oxide, Lithium Nickel Manganese Cobalt Oxide, Lithium Iron Phosphate, Lithium Nickel Cobalt Aluminum Oxide, and Lithium Titanate.

Specific energy: This defines the battery capacity in weight (Wh/kg). The capacity relates to the runtime. Products requiring long runtimes at moderate load are optimized for high specific energy.

Specific power: It's the ability to deliver a high current and indicates loading capability. Batteries for power tools are made for high specific power and come with a reduced specific energy.

Performance: This measures how well the battery works over a wide range of temperatures. Most batteries are sensitive to heat and cold and require climate control. Heat reduces life, and cold lowers performance temporarily.

Lifespan: This reflects cycle life and longevity and is related to factors such as temperature, depth of discharge, and load. Hot climates accelerate capacity loss. Cobalt blended lithium-ion batteries also usually have a graphite anode that limits the cycle life.

Safety: This relates to factors such as the thermal stability of the materials used in the batteries. The materials should have the ability to sustain high temperatures before becoming unstable. Instability can lead to thermal runaway in which flaming gases are vented. Fully charging the battery and keeping it beyond the designated age reduces safety.

Cost: Demand for electric vehicles has generally been lower than anticipated and this is mainly due to the cost of lithium-ion batteries. Hence cost is a huge factor when selecting the type of lithium-ion battery.

Using the above characteristics we will do the comparison of our six types of lithium-ion batteries. The characteristics are rated as either high, moderate, or low. The table below provides a simple comparison of the six lithium-ion battery types.

• SP stands for specific power
• SE stands for specific energy
• SF stands for safety
• LS stands for lifespan
• CS stands for cost
• PF stands for performance
• L stands for low
• M stands for moderate
• H stands for high