Week 1 Understanding Different Battery Chemistry
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
What is the chemistry involved in lithium-ion batteries?
Inside a lithium-ion battery,oxidation-reduction (Redox) reactions take place.
Reduction takes place at the cathode. There, cobalt oxide combines with lithium ions to form lithium-cobalt oxide (LiCoO2). The half-reaction is:
CoO2 + Li+ + e- → LiCoO2
Oxidation takes place at the anode. There, the graphite intercalation compound LiC6 forms graphite (C6) and lithium ions. The half-reaction is:
LiC6 → C6 + Li+ + e-
Here is the full reaction (left to right = discharging, right to left = charging):
LiC6 + CoO2 ⇄ C6 + LiCoO2
|
name |
Anode | Cathode | electolyte | seperator | uses | structure |
| LCO | GRAPHITE | LITHIUM COBALT OXIDE | ETHYLENE CARBONATE | POLYOLEFIN | mobile phones, laptops and digital cameras |  |
| LMO | GRAPHITE | LITHIUM MANGANESE | LITHIUM HALIDE | POLYOLEFIN | Electric vehicles such as the Nissan Leaf, Chevy Volt and BMW i3, Power tools, medical devices, electric powertrains |  |
| NCA | GRAPHITE | NICKEL COBALT ALUMINIUM | ETHYLENE CARBONATE | POLYOLEFIN | Medical devices, industrial, electric powertrain (Tesla) |  |
| NMC | GRAPHITE | NICKEL MANGANESE | LITHIUM SALT | POLYOLEFIN | E-bikes, medical devices, EVs, industrial |  |
| LTO | GRAPHITE | LITHIUM TITATINUM | LITHIUM SALT | POLYOLEFIN | UPS, electric powertrain (Mitsubishi i-MiEV, Honda Fit EV), solar-powered street lighting |
 |
| LFP | GRAPHITE | LITHIUM PHOSPHATE | ETHYELENE CARBONATE | POLYOLEFIN | Portable and stationary needing high load currents and endurance |  |
2.Compare the differences between each type of Li+ion batteries based on their characteristics
- Lithium iron phosphate (LFP)
- Lithium nickel manganese cobalt oxide (NMC)
- Lithium cobalt oxide (LCO)
- Lithium manganese oxide (LMO)
- Lithium nickel cobalt aluminum oxide (NCA)
- Lithium titanate (LTO)
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.
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.
| 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 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 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, 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, i.e. the degradation over time since manufacture.
| 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.
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.
| 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. |
| Main applications | |
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. |
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 are always being seen.