Week 1 Understanding Different Battery Chemistry

Understanding Different Battery Chemistry

Lithium Ion Battery

How does it work ?

A lithium-ion (Li-ion) battery is an advanced battery technology that uses lithium ions as a key component of its electrochemistry. During a discharge cycle, lithium atoms in the anode are ionized and separated from their electrons. The lithium ions move from the anode and pass through the electrolyte until they reach the cathode, where they recombine with their electrons and electrically neutralize. The lithium ions are small enough to be able to move through a micro-permeable separator between the anode and cathode. In part because of lithium’s small size (third only to hydrogen and helium), Li-ion batteries are capable of having a very high voltage and charge storage per unit mass and unit volume.

Li-ion batteries can use a number of different materials as electrodes. The most common combination is that of lithium cobalt oxide (cathode) and graphite (anode), which is most commonly found in portable electronic devices such as cellphones and laptops. Other cathode materials include lithium manganese oxide (used in hybrid electric and electric automobiles) and lithium iron phosphate. Li-ion batteries typically use ether (a class of organic compounds) as an electrolyte.

Advantages

Compared to the other high-quality rechargeable battery technologies (nickel-cadmium or nickel-metal-hydride), Li-ion batteries have a number of advantages. They have one of the highest energy densities of any battery technology today (100-265 Wh/kg or 250-670 Wh/L). In addition, Li-ion battery cells can deliver up to 3.6 Volts, 3 times higher than technologies such as Ni-Cd or Ni-MH. This means that they can deliver large amounts of current for high-power applications, which has Li-ion batteries are also comparatively low maintenance, and do not require scheduled cycling to maintain their battery life. Li-ion batteries have no memory effect, a detrimental process where repeated partial discharge/charge cycles can cause a battery to ‘remember’ a lower capacity. This is an advantage over both Ni-Cd and Ni-MH, which display this effect. Li-ion batteries also have low self-discharge rate of around 1.5-2% per month. They do not contain toxic cadmium, which makes them easier to dispose of than Ni-Cd batteries.

Due to these advantages, Li-ion batteries have displaced Ni-Cd batteries as the market leader in portable electronic devices (such as smartphones and laptops). Li-ion batteries are also used to power electrical systems for some aerospace applications, notable in the new and more environmentally friendly Boeing 787, where weight is a significant cost factor. From a clean energy perspective, much of the promise of Li-ion technology comes from their potential applications in battery-powered cars. Currently, the bestselling electric cars, the Nissan Leaf and the Tesla Model S, both use Li-ion batteries as their primary fuel source.

Disadvantages

Despite their technological promise, Li-ion batteries still have a number of shortcomings, particularly with regards to safety. Li-ion batteries have a tendency to overheat, and can be damaged at high voltages. In some cases this can lead to thermal runaway and combustion. This has caused significant problems, notably the grounding of the Boeing 787 fleet after onboard battery fires were reported. Because of the risks associated with these batteries, a number of shipping companies refuse to perform bulk shipments of batteries by plane. Li-ion batteries require safety mechanisms to limit voltage and internal pressures, which can increase weight and limit performance in some cases. Li-ion batteries are also subject to aging, meaning that they can lose capacity and frequently fail after a number of years. Another factor limiting their widespread adoption is their cost, which is around 40% higher than Ni-Cd. Addressing these issues is a key component for current research into the technology. Finally, despite the high energy density of Li-ion compared to other kinds of batteries, they are still around a hundred times less energy dense than gasoline (which contains 12,700 Wh/kg by mass or 8760 Wh/L by volume).

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 Cobalt Oxide (LCO)

It is also known as lithium cobaltate or lithium-ion cobalt batteries, lithium cobalt oxide batteries are made from lithium carbonate and cobalt. Due to their very high specific energy, these batteries are used for cell phones, laptops and electronic cameras. They have a cobalt oxide cathode and use graphite carbon as their anode material; during discharge, lithium ions move from anode to cathode, with the flow reversing when the battery is charging.This type of battery has some drawbacks, including a relatively short battery life and limited specific power. Additionally,battery university notes that these batteries are not as safe as other types. Even so, their characteristics make them the popular choice for cell phones and other portable electronic devices.

• Lithium Mangnese Oxide (LMO)

Lithium manganese oxide batteries are also commonly called lithium manganate or lithium-ion manganese batteries and are sometimes referred to as li-manganese or manganese spinel. The technology for this type of battery was discovered in the 1980s, with the first publication on the subject appearing in the Materials Research Bulletin in 1983. The first commercial lithium-ion cells made with lithium manganese oxide as a cathode material were produced in 1996 by Moli Energy. Lithium manganese oxide batteries are notable for their high temperature stability and are also safer than other lithium-ion battery types. For this reason, they are often used in medical equipment and devices, but they may also be used in power tools, electric bikes and more. It is also possible to use lithium manganese oxide batteries to power laptops and electric powertrain cars.

• Lithium Iron Phosphate (LFP)

Lithium iron phosphate batteries, also known as li-phosphate batteries, use phosphate as a cathode. They benefit from low resistance properties, which enhance their safety and thermal stability. Other benefits include durability and a long lifecycle — fully charged batteries can be stored with little change to the total lifespan of the battery’s charge. Li-phosphate batteries are often the most cost-effective option as well when their long battery life is taken into consideration. However, the lower voltage of the li-phosphate battery means that it has less energy than other types of lithium batteries. Accordingly, these batteries are often used in electric motorcycles as well as other applications that need a long lifecycle and significant safety. Electric vehicles often use these batteries as well.

• Lithium Nickel Mangnese Cobalt Oxide (NMC)

It is also known as lithium manganese cobalt oxide or NMC batteries, lithium nickel manganese cobalt oxide batteries are made of several materials common in lithium-ion battery types. They include a cathode made of a combination of nickel, manganese and cobalt.Like other lithium-ion battery varieties, NMC batteries can have either a high specific energy density or a high specific power. They cannot, however, have both properties. This battery type is most common in power tools and in powertrains for vehicles. The cathode combination ratio is usually 60 percent nickel, 20 percent manganese and 20 percent cobalt. This means that the raw material cost is lower than it is for other lithium-ion battery options, as cobalt can be quite expensive. These batteries may come down in price further in the future, as some battery makers are planning to switch their battery chemistry to a higher percentage of nickel. so that they can use less cobalt. This battery type is commonly preferred for electric vehicles due to its very low self-heating rate.

• Lithium Nickel Cobalt Aluminium Oxide

Lithium nickel cobalt aluminum oxide batteries are also called NCA batteries, and are becoming increasingly important in electric powertrains and in grid storage. NCA batteries are not common in the consumer industry, but are promising for the automotive industry. NCA batteries provide a high-energy option with a good lifespan, but they are not as safe as they could be compared to other lithium-ion battery types and are quite costly. NCA batteries must be accompanied by monitoring devices to ensure driver safety. Given the consistent use of NCA batteries in electric vehicles, it is possible that demand for these batteries will rise as electric vehicles become more common.

• Lithium Titanate

Finally, lithium titanate, also known as li-titanate, is a class of battery that allows for ever-increasing applications. The main advantage of the li-titanate battery is its remarkably fast recharge time, thanks to its advanced nanotechnology,writes battery space.Currently, manufacturers of electric vehicles and bikes use li-titanate batteries, and there is potential for this type of battery to be used in electric buses for public transportation. However, these batteries have lower inherent voltage, or lower energy density, than other lithium-ion battery varieties, which can present issues with powering vehicles efficiently. Even so, the density of lithium titanate batteries is still higher than other non-lithium-ion batteries, which is a plus. Applications for these batteries can include military and aerospace uses, and they may also be used for storing wind and solar energy and creating smart grids. Furthermore, Battery Space suggests these batteries could also be used in system-critical backups for power systems.

Chemical Reactions in different batteries

• Lithium Cobalt Oxide (LCO)- `LiCoO_2`

At Anode

`LiC_6 → xLi^+ + xe^- + C_6`

At Cathode

`Li_(1-x)CoO_2 + xLi^+ + xe^(-) → LiCoO_2`

`C_6 + LiCoO_2 ↔ Li_x C_6 + Li_(1-x)CoO_2`

• Lithium Mangnese Oxide (LMO)- `LiMn_2 O_4`

At Anode

`Li → Li^+ + e^-`

At Cathode

`Mn_2 O_4 + Li^+ + e^(- ) → LiMn_2 O_4`

• Lithium Nickel Mangnese Cobalt Oxide (NMC)-`LiNiMnCoO_2`

At Anode

`Li_x C_n → nC + xLi^+ + xe^-`

At Cathode

`Li_(1-x)MO_2 + xLi^+ + xe^(-) → LiMO_4`

Redox reaction

`Li_(1-x)MO_2 + Li_x C_n → LiMO_4 + nC`

• Lithium Iron Phosphate(LFP)-`LiFePO_4`

At Anode

`LiC_6 → Li^+ + e^(- )+ C_6`

At Cathode

`LiFe(3)PO_4 + xLi^+ + xe^(-)→ LiFe(2)PO_4`

`FePO_4 + Li^+ + e^(-) → LiFePO_4`

Overall reaction

`LiFePO_4 + 6C → LiC_6 + FePO_4`

• Lithium Nickel Cobalt Aluminium Oxide(NCA)-`LiNiCoAlO_2`

`Li_0.5 CoO_2 → 1/2 LiCoO_2 + 1/6 Co_3 O_4 + 1/6 O_2`

`Li_(1-x)NiO_2 →(1-2x)LiNiO_2 + xLiNi_2 O_4 (x ≤ 0.5)`

`Li_(1-x)NiO_2 → [Li_(1-x)Ni_((2x-1)/3)][Ni_((4-2x)/3)]O_((8-4x)/3) + ((2x-1))/3 O_2(x>0.5)`

`Li_(1-x)NiO_2 → (2-x)Li_((1-x)/(2-x))Ni_(1/(2-x))O + x/(2O_2 )`

• Lithium Titanate (LTO)-`Li_2TiO_3`

When charged/discharged in the potential range of 1-3 V

`Li_4Ti_5 O_12 + 3Li^+ + 3e^(-) ↔ Li_7Ti_5 O_12`

Increased capacity of lithium titanium oxide when cycled to 0.01 V is related to a full reduction of titanium ions from +4 to +3 oxidation state which involves additional two Li+ ions.

`Li_7Ti_5 O_12 + 2Li^++ 2e^(-)↔ Li_9Ti_5 O_12`

Sr. No.	Li-ion Battery Type	Chemical Formula	Cathode Material	Anode Material	Seperator	Applications
1	LCO	`LiCoO_2`	Cobalt oxide	Graphite Carbon	Polyolefin	Mobile phones, Tablets, Laptops, Cameras
2	LMO	`LiMn_2 O_4`	Lithium Mangnese oxide	Graphite Carbon	Polyolefin	Power tools, Medical devices, Powertrains
3	NMC	`LiNiMnCoO_2`	Lithium Nickel Mangnese Cobalt oxide	Graphite Carbon	Polyolefin	E-bikes, Medical devices, EVs
4	LFP	`LiFePO_4`	Lithium Iron phosphate	Graphite Carbon	Polyolefin	Stationary with high currents & endurance
5	NCA	`LiNiCoAlO_2`	Lithium Nickel Cobalt Aluminium oxide	Graphite Carbon	Polyolefin	Medical, EV (Tesla)
6	LTO	`Li_2TiO_3`	Lithium Mangnese oxide	Lithium Titanate	Polyolefin	UPS, EV, Solar street lighting

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

Lithium-ion batteries are used in most aspects of our everyday lives. Most devices like smartphones and laptops cannot operate without these batteries. Lithium-ion batteries have also become very important in the field of electromobility as it is now the battery of choice in most electric vehicles. Its high specific energy gives it an advantage over other batteries. 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. Firstly, an understanding of the key terms below will allow for a simpler and easier comparison.

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. A high specific power usually comes with reduced specific energy and vice versa. The pouring of bottled water in a glass is a perfect analogy of the relationship between specific power and specific energy. The water in the bottle can be thought of as specific energy. Pouring the water at a slow rate doesn’t provide enough force (low specific power) but the water lasts longer in the bottle (high specific energy). On the other hand, if we pour the water out at a faster rate it provides a greater impact (high specific power). However, the water wouldn’t last very long in the bottle ( low 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.

Now that we have an understanding of the major battery characteristics, we will use them as the basis for 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.

1.Lithium Cobalt Oxide (LCO)

It 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.

Characteristics: High energy density, high level of safety

Disadvantages: Relatively short life span, limited high load capability

Applications: Consumer electronics: mobile phones, games, laptops, tablets, e-readers etc.

Voltage: 3.6V nominal with typical operating rate between 3-4.2 V/cell

Specific Energy (Capacity): 150-200 Wh/kg typical

Battery Life: 500-1000 cycles

2.Lithium Mangnese Oxide (LMO)

It 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.

Characteristics: High current capability for charge & discharge

Disadvantages: Lower energy density than other types of lithium ion battery, low cycle life & calender life

Applications: Power tools, some medical tools, some vehicles

Voltage: 3.7 V nominal

Specific Energy (Capacity): 100-150 Wh/kg

Battery Life: 400-750 cycles

3.Lithium Nickel Mangnese Cobalt Oxide (NMC)

It 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.

Characteristics: High specific power or energy

Disadvantages: Power/energy density not as high as some other types

Applications: Power tools & electric vehicles

Voltage: 3.6-3.7 V

Specific Energy (Capacity): 160-230 Wh/kg

Battery Life: 1000-2000 cycles

4.Lithium Iron Phosphate (LFP)

It 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.

Characteristics: High current capability, longer calender life span

Disadvantages: Slightly higher discharge rate, low cell voltage (3.3V)

Applications: Power tools, some medical tools, hobbyist

5.Lithium Nickel Cobalt Aluminium Oxide (NCA)

It 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.

Characteristics: High energy density, high power density, good life span

Disadvantages: High cost, safety requires more care in design & use

6.Lithium Titanate (LTO)

It 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.

Characteristics: Relatively high power, fast charging time

Disadvantages: Low specific energy, high cost

Applications: Storing solar energy, creating smart grids

Lithium Battery Types	Specific Power	Specific Energy	Safety	Lifespan	Cost	Performance
Lithium Cobalt Oxide (LCO)	Low	High	Low	Low	Low	Moderate
Lithium Mangnese Oxide (LMO)	Moderate	Moderate	Moderate	Low	Low	Low
Lithium Nickel Mangnese Cobalt Oxide (NMC)	Moderate	High	Moderate	Moderate	Low	Moderate
Lithium Iron Phosphate (LFP)	High	Low	High	High	Low	Moderate
Lithium Nickel Cobalt Aluminium Oxide (NCA)	Moderate	High	Low	Moderate	Moderate	Moderate
Lithium Titanate (LTO)	Moderate	Low	High	High	High	High

Conclusion

From this we have learnt working & its types, advantages, disadvantages & characeristics of Lithium ion battery.