Week 1 Understanding Different Battery Chemistry

Q1. 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

Li-ion Batteries

A lithium-ion battery or Li-ion battery is a type of rechargeable battery, Lithium-ion batteries are commonly used for portable electronics and electric vehicles and are growing in popularity for military and aerospace applications

Similar to the lead- and nickel-based architecture, lithium-ion uses a cathode (positive electrode), an anode (negative electrode) and electrolyte as conductor. The cathode is a metal oxide and the anode consists of porous carbon. During discharge, the ions flow from the anode to the cathode through the electrolyte and separator; charge reverses the direction and the ions flow from the cathode to the anode. Figure 1 illustrates the process.

Types of Li-ion Cells

• Lithium Cobalt Oxide (LiCoO2)-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 t cobalt is a relatively short life span, low thermal stability and limited load capabilities (specific power).

• 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.

• Lithium Nickel Cobalt Aluminum Oxide (LINICOAIO2) - 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.

• Lithium Nickel Manganese Cobalt Oxide (LINIMnC002) - 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 as Energy Cells or Power Cells. For example, NMC in an 18650

cell for moderate load condition has a capacity of about 2,800mAh and can deliver 4A to 5A; NMC in the same cell optimized for specific power has a capacity of only about 2,000mAh but delivers a continuous discharge current of 20A

• Lithium Iron Phosphate(LiFePO4)-LFP

U-phosphate offers good electrochemical performance with low resistance. This is made possible with nano-scate phosphate cathode material. The key benefits are high current rating and long cycle life, besides good thermal stability, enhanced safety and tolerance if abused Li-phosphate is more tolerant to full charge conditions and is loss stressed than other lithium-ion systems if kept at high voltage for a prolonged time. As a trade-off, its lower nominal voltage of 3.2V/cell reduces the specific energy below that of cobalt-blended lithium-ion.

• Lithium Titanate (LI2TiO3) - LTO

Batteries with lithium titanate anodes have been known since the 1980s, L-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 U ion. Li-titanate is safe, has excellent low-temperature discharge characteristics and obtains a capacity of 80 percent at-30°C.

Materials & chemical reactions occurring at the anode, cathode and overall reaction of all the type of Li-ion cells are given below :

Name	Anode	Cathode	Seperator	Electrolyte	Anode Reaction	Cathode Reaction	Overall Reaction
Lithium Cobalt Oxide (LiCoO2)-LCO	Graphite	Lithium cobalt oxide	Polyolefin	Ethylene carbonate
Lithium Manganese Oxide (LiMn204) - LMO	Graphite	Lithium Manganrse	Polyolefin	Lithium Halide
Lithium Nickel Cobalt Aluminum Oxide (LINICOAIO2) - NCA	Graphite	Nickel Cobalt Aluminum	Polyolefin	Ethylene carbonate
Lithium Nickel Manganese Cobalt Oxide (LINIMnC002) - NMC	Graphite	Nickel Manganese	Polyolefin	Lithium Salt
Lithium Iron Phosphate(LiFePO4)-LFP	Graphite	Lithium Iron Phosphate	Polyolefin	Ethylene carbonate
Lithium Titanate (LI2TiO3) - LTO	Graphite	Lithium Titanate	Polyolefin	Lithium Salt

Q2. Compare the differences between each type of Li+ion batteries based on their characteristics

Characteristics	Lithium Cobalt Oxide - LCO	Lithium Manganese Oxide - LMO	Lithium Nickel Cobalt Aluminum Oxide - NCA	Lithium Nickel Manganese Cobalt Oxide - NMC	Lithium Iron Phosphate - LFP	Lithium Titanate - LTO
Voltages	3.60V nominal; typical operating range 3.0–4.2V/cell	3.70V (3.80V) nominal; typical operating range 3.0–4.2V/cell	3.60V nominal; typical operating range 3.0–4.2V/cell	3.60V, 3.70V nominal; typical operating range 3.0–4.2V/cell	3.20, 3.30V nominal; typical operating range 2.5–3.65V/cell	2.40V nominal; typical operating range 1.8–2.85V/cell
Specific energy (capacity)	150–200Wh/kg	100–150Wh/kg	200-260Wh/kg	150–220Wh/kg	90–120Wh/kg	50–80Wh/kg
Charge (C-rate)	0.7–1C, charges to 4.20V	0.7–1C, charges to 4.20V	0.7C, charges to 4.20V	0.7–1C, charges to 4.20V	1C, charges to 3.65V	1C, charges to 2.85V
Discharge (C-rate)	1C, 2.50V cut off	1C, 2.50V cut-off	1C, 3.00V cut-off	1C, 2.50V cut-off	1C, 2.50V cut-off	10C , 1.80V cut-off
Cycle life	500–1000	300–700	500	1000–2000	2000 and higher	3000–7000
Thermal runaway	150°C	250°C	150°C	210°C	270°C	One of safest Li-ion batteries
Applications	Mobile phones, tablets, laptops, cameras	Power tools, medical devices, electric powertrains	Medical devices, industrial, electric powertrain (Tesla)	E-bikes, medical devices, EVs, industrial	Portable and stationary needing high load currents and endurance	UPS, electric powertrain (Mitsubishi i-MiEV, Honda Fit EV), solar-powered street lighting