Week 1 Understanding Different Battery Chemistry

Aim:

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.

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

Solution:

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.

LCO:

• LCO stands for Lithium cobalt battery.
• Lithium cobalt oxide is one of the most common Lithium-ions, it has a chemical symbol which is LiCoO2 and is abbreviated as LCO.
• For simplification, Li-cobalt –which is the short term- can also be used for this type battery. Cobalt is the core active material which defines the character of the battery.

Lithium-ion batteries and concept

• The most popular technology of the battery sector currently is the lithium ion battery.
• Relative to other types of batteries, lithium ion batteries have better energy, power density and higher cycling ability. These qualities are extremely important in the use in modern applications like electrical and hybrid vehicles and most importantly energy storage systems which are used in the renewable energy applications.
• The lithium ion batteries chemistry is the same across the different lithium-ion battery types; during discharge, Lithium-ions are moved to the positive cathode from the negative anode through the organic electrolyte.
• The anodes in all various technologies of lithium ion are all made from graphite. The differences are the cathode which contains changing cobalt, nickel or manganese concentrations.
• All various cathode types allow high lithium insertion and intercalation levels which result in large energy storage quantities. 

LCO batteries technology and applications

• LCO (Lithium cobalt oxide) 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 the portable devices are cobalt based.
• The system contains a cobalt oxide cathode (positive electrode) and graphite carbon anode (negative electrode).

Advantages and disadvantages of LCO batteries

 The main advantages of the LCO batteries are:

• High energy density.
• Long runtime making it optimum for new technologies

 The main disadvantages of the LCO batteries are:

• It has a relatively low discharge current so high load can lead to pack overheat
• The safety circuit of the LCO battery is typically limited to a 1C for charging and discharging.
• The internal resistance increases with cycling and aging. This high internal resistance can cause the battery to become unserviceable due to a large voltage drop under the load after a couple of years of use.

   LMO:

• LMO stands for Lithium manganese oxide batteries, which are commonly referred to as lithium-ion manganese batteries or manganese spinel.
• This battery was discovered in the 1980s, yet the first commercial lithium-ion battery made with a cathode material made from lithium manganese was produced in 1996.

LMO batteries technology and applications

• LMO (Lithium magnesium oxide) was invented in the year 1996.
• Its anode material is LiaC6, the cathode material is LibMn2O4 and the carrier is Li+.
• It is used in different applications like power tools and electric cars.
• LMO batteries have the ability to deliver a lot of energy in a short period of time, which makes them extremely useful for use in power tools like drills. In 1996, lithium manganese oxide was first used as a cathode material.
• A three dimensional spinel structure was formed by this structure, this improves the flow of ions between the electrodes.
• The high flow decreases the internal resistance and increases loading capability.
• LMO batteries are usually used in medical devices and equipment, power tools, electric bikes and more. Because of their thermal resistance and higher safety. LMO batteries can also be used for laptops and electrical cars.

Advantages and disadvantages of LMO batteries

The main advantages of the LMO batteries are:

• High temperature stability and safety relative to other Li-ion types as it has integrally high thermal stability thus needs less safety circuitry than cobalt system.
• High rate capability due to low internal cell resistance which benefits fast charging and high current discharging.

 The main disadvantage of the LMO batteries is:

• Lower capacity relative to cobalt-based system, yet it still has an energy density which is nearly 50% higher than the nickel-based system.

NCA:

• NCA battery stands for Lithium nickel cobalt aluminum oxide based battery (LiNiCoAlO2).
• Also, NCA batteries are becoming more and more important in in-grid storage and electrical power terrain applications.

NCA battery technology and applications

• NCA (Lithium nickel cobalt aluminum oxide) battery was invented in the year 1999.
• Its anode material is LiaC6, the cathode material is LibNi0.8Co0.15Al0.05O2 and the carrier is Li+.
• It is used in different applications like power grid applications, medical devices and electric cars.
• Most notably Tesla deploys NCA batteries in their electric vehicles system.
• NCA batteries can store the same amount of energy as NMC.
• NCA batteries are not widely common in the consumer industry, but are quite promising in the electric car industry.

Advantages and disadvantages of NCA batteries

 The main advantages of the NCA batteries are:

• High specific energy
• Reasonably good specific power
• Long life span
• NCA cathodes contain the most energy amount by weight and volume (as NMC).

 The main disadvantages of the NCA batteries are:

• Less safety than other Li-ion battery types (they require extra safety features and circuits for use in electric cars for example)
• Higher cost in comparison to other Li-ion battery types

NMC:

• One of the most successful li-ion cathode formulas developed to date is obtained by combining nickel, manganese, and cobalt.
• Lithium-Nickel-Manganese-Cobalt-Oxide (LiNiMnCoO2), abbreviated as NMC, has become the go-to cathode powder to develop batteries for power tools, e-bikes and other electric powertrains.
• It delivers strong overall performance, excellent specific energy, and the lowest self-heating rate of all mainstream cathode powders, which makes it the preferred option for automotive batteries.

• While NMC powder can refer to a variety of blends, the formula typically consists of 33% nickel, 33% manganese and 33% cobalt. This blend, sometimes referred to as 1-1-1, is a popular option for mass-produced cells in applications requiring frequent cycling (automotive, energy storage) due to the reduced material cost resulting from lower cobalt content.

LFP:

• Lithium Iron phosphate (LFP) is a popular, cost-effective cathode material for lithium-ion cells that is known to deliver excellent safety and long life span, which makes it particularly well-suited for specialty battery applications requiring high load currents and endurance.
• Discovered by University of Texas researchers in the mid-90s, LFP cathode offers several key advantages including a high current rating, long cycle life, and superior thermal stability, which makes it one of the safest and most abuse-tolerant cathode material options available to manufacturers.

• On the other hand, LFP delivers a lower nominal voltage, which results in lower specific energy when compared to other cathode materials on the market. Consequently, LFP batteries tend to have a higher self-discharge than other Li-ion battery types.

LTO:

• The lithium–titanate battery (Li4Ti5O12,referred to as LTO in the battery industry) is a type of rechargeable battery based on advanced nano-technology, which has the following advantages than other lithium batteries.

Advantages:

• Li-Titanate batteries have a wider operating temperature range (-30-55°C) and a recharge efficiency exceeding 98%, compared to other carbon based batteries.
• Li-Titanate batteries as long cyecle life: > 3000-7000 cycles
• Li-Titanate batteries are high security, high stability.
• Li-Titanate batteries are faster to charge than other lithium-ion batteries. Data shows that these batteries can be safely charged at rates higher than 10C.
• Li-Titanate batteries are green & eco-friendly.

Disadvantage:

The disadvantage is that lithium-titanate batteries have a lower inherent voltage (2.4V/cell), which leads to a lower energy density than conventional lithium-ion battery technologies. But the energy density of LTO ‐ based batteries is still higher than lead acid and NiCad batteries.

Applications: Ideal for High Rate and High Cycle Life Applications

• Because of the benefits of lithium titanate in terms of high security, high stability, long life and green features, lithium titanate batteries can be widely used in military, aerospace, electric vehicles and charging stations, tourist coaches, yachts, wind and solar energy storage power, traffic signals, solar hybrid street lighting, UPS power supply, home storage, coal, disaster relief emergency, weather radar, electricity, smart grid, communication base stations, hospitals, finance, telecommunications as well as system critical backup power systems.

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

Types of Lithium ion 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 Aluminium Oxide, and Lithium Titanate.

Before choosing the type of battery there are some important points to be considered which affects the battery performance.

• 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 high current and indicates loading capability. Batteries for power tools are made for high specific power and come with reduced specific energy.

• 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 make a Cycle

• The current rate (C): This is used to determine the fast charging capability of a battery.

• Thermal Runaway: It is a condition where an increase in temperature changes the conditions which increase the temperature further, often leading to disaster.

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

The following differences between each type of Li+ion batteries based on their characteristics are given below: