Week 1 Understanding Different Battery Chemistry

LTHIUM-ION BATTER

Lithium ions (Li) areinvolved in the reactions driving the battery. Bothelectrodes in a lithium-ion cell are made ofmaterials which can intercalate or 'absorb' lithiumions. Intercalation is when charged ions of anelement can be 'held' inside the structure of a host material without significantly disturbing it. In
the case of a lithium-ion battery, the lithium ions are 'tied' to an electron within the structure of the
anode. When the battery discharges, the intercalated lithium ions are released from the
anode, and then travel through the electrolyte solution to be absorbed (intercalated) in the
cathode.
A lithium-ion battery starts its life in a state of full discharge: all its lithium ions are intercalated within the cathode and its chemistry does not yet have the ability to produce any electricity. Before you can use the battery, you need to charge it. As the battery is charged, an oxidation reaction occurs at the cathode, meaning that it loses some negatively charged electrons. To maintain the charge balance in the cathode, an equal number of some of the positively charged intercalated lithium ions are dissolved into the electrolyte solution. These travel over to the anode, where they are intercalated within the graphite. This intercalation reaction also deposits electrons into the graphite anode, to 'tie' up the lithium ion.
During discharge, the lithium ions are de- intercalated from the anode and travel back through the electrolyte to the cathode. This also releases the electrons that were tying them to the anode, and these flow through an external wire, providing the electric current that we used to do work. It's the connection of the external wire that enables the reaction to proceed-when the electrons are free to travel, so are the positively charged lithium ions that will balance the movement of their negative charge. When the cathode becomes full of lithium ions, the reaction stops and the battery is flat. Then we recharge our lithium-ion batteries again, and the external electric charge that we apply pushes the lithium ions back into the anode from the cathode.

TYPES OF LITIUM-ION BATTERY
• LITHIUM COBALT OXIDE(LiCo02) – LCO :
Its high specific energy makes Li-cobalt the popular choice for mobile phones, laptops and digital cameras. The battery consists of a cobalt oxide cathode and a graphite carbon anode. The
cathode has a layered structure and during discharge, lithium ions move from the anode to the cathode. The flow reverses on charge. The drawback of Li-cobalt is a relatively short life span, low thermal stability and limited load capabilities

The cathode has a layered structure. During discharge the lithium ions move from the anode to the cathode; on charge the flow is from cathode to anode.

Reaction of LITHIUM COBALT OXIDE BATTERIES:
During Discharge
At the anode, lithium is oxidised.Lithium ionsare released from the carbon, along withelectrons:
LiC6 ==> XLi+ + xe- + C6
At the cathode, lithium-ions are absorbed by the lithium dioxide, and the electrode is reduced
as it also receives the electrons from the circuit:
Lil-xCo02 + XL3+ + xe- ==> LiCo02
The overall reaction is :
C6 + LiCoO2 <==> LixC6 + Lil-xCo02

• LITHIUM MANGANESE OXIDE (LiMn204) –LMO:
Li-ion with manganese spinel was first published in the Materials Research Bulletin in 1983. In
1996, Moli Energy commercialized a Li-ion cell with lithium manganese oxide as cathode material. The architecture forms a three- dimensional spinel structure that improves ion flow on the electrode, which results in lower internal resistance and improved current handling. A further advantage of spinel is high thermal stability and enhanced safety, but the cycle and calendar life are limited.
Low internal cell resistance enables fast charging and high-current discharging. In an 18650 package, Li-manganese can be discharged at currents of 20–30A with moderate heat buildup.
It is also possible to apply one-second load pulses of up to 50A. A continuous high load at this current would cause heat buildup and the cell temperature cannot exceed 80°C (176°F). Li- manganese is used for power tools, medical instruments, as well as hybrid and electric
vehicles. illustrates the formation of a three-dimensional crystalline framework on the cathode of a Li-manganese battery. This spinel structure, which is usually composed of diamond shapes connected into a lattice, appears after initial formation.

Reaction of Lithium Manganese Oxide BATTERIES:
During Discharge
At the anode, lithium is oxidised.Lithium ions are released from the carbon, along with electrons:
Lic6 ==> XLl+ + xe- + C6
At the cathode, lithium-ions are absorbed by the lithium dioxide, and the electrode is reduced
as it also receives the electrons from the circuit:
Lil-xMn2O4 + XL3+ + xe- ==> Linh
The overall reaction is :
LiC6 + Mn204 <==>C6 + LiMnO2

• LITHIUM NICKEL MANGANESE OXIDE(LiNiMnCo02)- NMC
One of the most successful Li-ion systems is a cathode combination of nickel-manganese-
cobalt (NMC). Similar to Li-manganese, these systems can be tailored to serve 4,000mAh and higher but at reduced loading capability and shorter cycle life. Silicon added to graphite has the drawback that the anode grows and shrinks with charge and discharge, making the cell
mechanically unstable. The secret of NMC lies in combining nickel and manganese. An analogy of this is table salt in which the main ingredients, sodium and chloride, are toxic on their own but mixing them serves as are toxic on their own but mixing them serves as seasoning salt and food preserver. Nickel is known for its high specific energy but poor stability; manganese has the benefit of forming a
spinel structure to achieve low internal resistance but offers a low specific energy. Combining the
metals enhances each other strengths.

Reaction of Lithium Manganese Cobalt Oxide BATTERIES:
During Discharge
At the anode, lithium is oxidised.Lithium ions are released from the carbon, along with electrons:
LiC6 ==> XLi+ + xe- + C6
At the cathode, lithium-ions are absorbed by the lithium dioxide, and the electrode is reduced as it also receives the electrons from the circuit:
Lil-xMO2 + XLi+ + xe- ==> LiM02
The overall reaction is :
Li1-XMO2 + LiC6 <==> Lin-MO2 + C6

• LITHIUM IRON PHOSPHATE(LiFePO4) – LFP
This cell has a high discharge rate and, because phosphate (PO) can cope with high temperatures, the battery has good thermal stability, improving its safety. This makes it a good choice for things like electric vehicles and power tools, and for storing energy at power stations. It also has a long cycle life, meaning it can be discharged and charged many times. However, it has a lower energy
density than a lithium cobalt oxide cell, and a higher self-discharge rate. A lithium iron phosphate battery cell is similar to the lithium cobalt oxide cell. The anode is still graphite and the electrolyte is also much the same. The difference is that the lithium cobalt dioxide cathode has been replaced with
the more stable lithium iron phosphate. In fact, no lithium or iron ions remain in the iron phosphate (FePO4) cathode of a fully charged cell. The lithium ions can intercalate into or out of the cathode material through well-defined tunnels in its structure without significantly altering the iron
phosphate framework.

Reaction of Lithium Iron Phosphate BATTERIES
During Discharge
At the anode, lithium is oxidised. Lithium ions are released from the carbon, along with electrons:
LiC6 ==> XLi+ + xe- + C6
At the cathode, lithium-ions are absorbed by the lithium dioxide, and the electrode is reduced
as it also receives the electrons from the circuit:
LiFe(III)PO4 + xLi+ + xe- ==> LiFe(II) PO4
FePO4 + Li+ + e- ==> LiFePO4
The overall reaction is:
LiFePO4 + 6C ==> LIC6 + FePO4

• LITHIUM NICKEL COBALT ALUMINUM OXIDE (LINICOALO2) - NCA
Lithium nickel cobalt aluminum oxide battery, or NCA, has been around since 1999 for special
applications. It shares similarities with NMC by offering high specific energy, reasonably good
specific power and a long life span. Less flattering are safety and cost. NCA is a further development of lithium nickel oxide; adding aluminum gives the chemistry greater stability. High energy and power densities, as well as good life span, make NCA a candidate for EV powertrains. High cost and marginal safety are negatives.

Reaction of Lithium Nickel Cobalt Aluminum Oxide BATTERIES:
During Discharge
At the anode, lithium is oxidised.Lithium ions are released from the carbon, along with electrons:
LiC6 ==> XLi+ + xe- + C6
At the cathode, lithium-ions are absorbed by the lithium dioxide, and the electrode is reduced as it also receives the electrons from the circuit:
Lil-xM02 + XLi+ + xe- ==> LiO2
The overall reaction is :
Li1-MO2 +LiC6 <==> Li1-xMO2 + C6

• LITHIUM TITANATE (Li2ti03) - LTO
Batteries with lithium titanate anodes have been known since the 1980s. Li-titanate replaces the
graphite in the anode of a typical lithium-ion battery and the material forms into a spinel structure. The cathode can be lithium manganese oxide or NMC. Li-titanate has a nominal cell voltage of 2.40V, can be fast charged and delivers a high discharge current of 10C, or 10 times the rated capacity. The cycle count is said to be higher than that of a regular Li-ion. Li- titanate is safe, has excellent lowtemperature discharge characteristics and obtains a capacity of 80 percent at -30°C (-22°F).
LTO (commonly Li4Ti5012) has advantages over the conventional cobalt-blended Li-ion with graphite anode by attaining zero-strain property, no SEl film formation and no lithium plating when fast charging and charging at low temperature. Thermal stability under high temperature is also better than other Li-ion systems; however, the battery is expensive.

Reaction of Lithium Titanate BATTERIES:
During Discharge
At the anode, lithium is oxidised.Lithium ions are released from the carbon, along with electrons:
Li 4 Ti5012 ==> Ti5012 + 4Li+ + 4e-
At the cathode, lithium-ions are absorbed by the lithium dioxide, and the electrode is reduced as it also receives the electrons from the circuit:
4Mn204 + 4Li+ + 4e- ==> 4 LiMn204
The overall reaction is :
Li4T15012 + 4Mn204 <==> 4LiMn204 + Ti5012
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Lithium ion Types of battery:-

Li-ion types:
LCO
LMO
NMC
LFP
NCA
LTO

Chemical name;

LiCoo2
LiMn204
LiNiMnCo02
LiFePO4
LiNiCoAlo2

Lithium Titanate

Anode Material
graphite
graphite
graphite
graphite
graphite
Li2TiO3 (titanate)

Cathode Material
LiCOO2 (-60% Co)
LiMn204
LiNiMnCo02
LiFePO4
LiNiCoAlO2 (-9% Co)

Full form
Lithium Cobalt Oxide
Lithium Manganese Oxide
Lithium Nickel Manganese Cobalt Oxide
Lithium Iron Phosphate
Lithium Nickel Cobalt Aluminum Oxide

Anode Reaction(Discharge)
LiC6 ==> XLi+ + xe- + C6
LiC6 ==> XLi+ + xe- + C6
LiC6 ==> XLi+ + xe- + C6
LiC6 ==> XLi+ + xe- + C6
LiC6 ==> XLj+ + xe- + C6
LiC6 ==> XLi+ + xe- + C6

Cathode Reaction (Discharge)
Li1-xCool + XLi+ + xe- ==> LiCo02
Lil-xMn2O4 + XL3+ + xe- ==> LiMnO2
Lil-xMO2 + XLi+ + xe- ==> LiM02
LiFe(III)PO4 + xLi+ + xe- ==> LiFe(11)PO4
Li-xM01 + XL3+ + xe- ==> LiM02
4Mn204 + 4Li+ + 4e- ==> 4 LiMn204

Overall Reaction
C6 + LiCoO2 <==> LixC6 + Lil-xCo02
LiC6 + Mn204 <==>C6 + LiMnO2
Li1-XMO2 + LiC6 <==> Lin-MO2 + C6
LiFePO4 + 6C ==> LiC6 + FePO4
Li1-xMO2 + LiC6 <==> Lil-xMO2 + C6
Li4Ti5012+ 4 Mn204 <==> 4LiMn204 + Ti5012