Week 1 Understanding Different Battery Chemistry

Tabulate chemistry reaction of Lithium-ion Battery

Aim :

Explain the material and chemical reactions occuring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium ion cells and compare the difference between each type of li-ion Batteries based on their characteristics.

Objective :

• Prepare a table for chemical reaction occuring at the anode and cathode of different type of li-ion Battery.
• Explain the differences between each type of li-ion batterys.

Theory :

Lithium ion Cells :

Lithium ion batteries are used in most aspects of our everyday lives. Most devices like smartphones and laptops cannot operate without theses 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.

Types of Lithium-ion Battery :

The six Lithium-ion battery type that we will be comparing are..

• LCO - Lithium Cobalt Oxide (Li-Co-O2)
• LMO - Lithium Manganese Oxide (Li-Mn2-O4)
• NCA - Lithium Nickel Cobalt Aluminum Oxide (Li-Ni-Co-Al-O2)
• NMC - Lithium Nickel Manganese Cobalt Oxide (Li-Ni-Mn-Co-O2)
• LFP - Lithium Iron Phosphate (Li-Fe-PO4)
• LTO - Lithium Titanate (Li2-Ti-O3)

Chemical reactions :

Table for Chemical reactions occuring at anode and cathode and the overall reaction for all different type of Lithium-ion cells.

Firstly, an understanding of the key terms below will allow for a simpler and easier comparision.

Major Battery Charecteristics :

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 en ergy 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 energy) 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 batteris 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 electrical vehicle 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.

Lithium Cobalt Oxide (Li-Co-O2) :

Lithium cobalt oxide has high specific energy as compared to other batteries which make it the perferred choice for laptops and moblie 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 (Li-Mn2-O4) :

Lithium manganese oxide has moderate specific power moderate specific energy and a moderate level of safty 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 Cobalt Aluminum Oxide (Li-Ni-Co-Al-O2) :

Lithium Nickel Cobalt Aluminum Oxide offers one strong advantage as compared to the five other babtteries 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 Nickel Manganese Cobalt Oxide (Li-Ni-Mn-Co-O2) :

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 Iron Phoshate (Li-Fe-PO4) :

Lithium Iron Phoshate 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 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 motorcycle and other applications that require a long lifespan and high level of safety.

Lithium Titanate (Li2-Ti-O3) :

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 disadvantages of lithium titanate as compared to the other lithium-ion batteries is its extremely high cost. Another importeant 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.

Table for different characteristic of Lithium-ion Battery

Conclusion :

Hence we see the brief explanation of the material and chemical reactions occuring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium ion cells and compare the difference between each type of li-ion Batteries based on their characteristics.