Week 1 Understanding Different Battery Chemistry

OBJECTIVES:

1. To prepare a table that includes materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP, and LTO type of lithium-ion cells.

2. To compare different types of Li+ion batteries based on their characteristics.

BODY:

1. Comparison table

Sr no.	Name	Anode	Cathode	Seperator	Electrolyte	Anode reaction	Cathode Reaction	Overall Reaction
1	Lithium Cobalt Oxide (LCO)	Graphite	Lithium Cobalt Oxide	polyolefin	Ethylene Carbonate	LiC6 -> C6 + Li+ +e-	CoO2 + Li+ +e- -> LiCoO2	C6 + LiCoO2 -> LiC6 + CoO2
2	Lithium Manganese Oxide (LMO)	Graphite	Lithium Manganese	polyolefin	Lithium Halide	LiC6 -> C6 + Li+ +e-	MnO2 + Li+ +e- -> LiMnO2	C6 + LiMn2O2 -> LiC6 + Mn2O2
3	Lithium Nickel Cobalt Aluminum Oxide (NCA)	Graphite	Nickel Cobalt Alumium	polyolefin	Ethylene Carbonate	LiC6 -> C6 + Li+ +e-	NiCoAlO2 + Li+ +e- -> LiNiCoAlO2	C6 + LiNiCoAlO2 -> LiC6 + NiCoAlO2
4	Lithium Nickel Manganese Cobalt Oxide (NMC)	Graphite	Nickel Manganese	polyolefin	Lithium Salt	LiC6 -> C6 + Li+ +e-	NiMnCoO2 + Li+ +e- -> LiNiMnCoO2	C6 + LiNiMnCoO2 -> LiC6 + NiMnCoO2
5	Lithium Iron Phosphate	Graphite	Lithium Iron Phosphate	polyolefin	Ethylene Carbonate	LiC6 -> C6 + Li+ +e-	FePO4 + Li+ +e- -> LIFePO4	C6 + LiFePO4 -> LiC6 + FePO4
6	Lithium Titanate (LTO)	Graphite	Lithium Titanate	polyolefin	Lithium Salt	Li4Ti5O12 -> Ti5O12 + 4Li+ +4e-	4Mn2O4 + 4Li+ + 4e- -> 4LiMn2O4	4Mn2O4 + Li4Ti5O12 -> 4LiMn2O4 + Ti5O12

2. Comparision between different types of Li+ batteries.

Li-ion Batteries

• A lithium-ion battery or Li-ion battery is a type of rechargeable battery. which 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; the charge reverses the direction and the ions flow from the cathode to the anode.

Types of Li-ion Cells

1. 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 Li-cobalt is its relatively short life span, low thermal stability, and limited load capabilities (specific power).

2. Lithium Manganese Oxide (LiMn2O4) — 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 is limited.

3. 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.

4. Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — 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 a 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.

5. Lithium Iron Phosphate(LiFePO4) — LFP

• Li-phosphate offers good electrochemical performance with low resistance. This is made possible with nano-scale 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 less 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.

6. Lithium Titanate (Li2TiO3) — 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 low-temperature discharge characteristics, and obtains a capacity of 80 percent at –30°C.