Week 1 Understanding Different Battery Chemistry

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

Li-ion batteries have an unmatchable combination of high energy and power density, making it the technology of choice for portable electronics, power tools, and hybrid/full electric vehicles.

If electric vehicles (EVs) replace the majority of gasoline powered transportation, Li-ion batteries will significantly reduce greenhouse gas emissions. The high energy efficiency of Li-ion batteries may also allow their use in various electric grid applications, including improving the quality of energy harvested from wind, solar, geo-thermal and other renewable sources, thus contributing to their more widespread use and building an energy-sustainable economy.

Therefore Li-ion batteries are of intense interest from both industry and government funding agencies, and research in this field has abounded in the recent years.

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 a relatively short life span, low thermal stability and limited load capabilities (specific power).

Li-cobalt should not be charged and discharged at a current higher than its C-rating. This means that an 18650 cell with 2,400mAh can only be charged and discharged at 2,400mA. Forcing a fast charge or applying a load higher than 2,400mA causes overheating and undue stress. For optimal fast charge, the manufacturer recommends a C-rate of 0.8C or about 2,000mA.

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 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.

Li-manganese has a capacity that is roughly one-third lower than Li-cobalt. Most Li-manganese batteries blend with lithium nickel manganese cobalt oxide (NMC) to improve the specific energy and prolong the life span. This combination brings out the best in each system, and the LMO (NMC) is chosen for most electric vehicles, such as the Nissan Leaf, Chevy Volt and BMW i3. The LMO part of the battery, which can be about 30 percent, provides high current boost on acceleration; the NMC part gives the long driving range.

Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO₂) — NMC

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 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.

NMC is the battery of choice for power tools, e-bikes and other electric powertrains. The cathode combination is typically one-third nickel, one-third manganese and one-third cobalt, also known as 1-1-1. This offers a unique blend that also lowers the raw material cost due to reduced cobalt content. Another successful combination is NCM with 5 parts nickel, 3 parts cobalt and 2 parts manganese (5-3-2). Other combinations using various amounts of cathode materials are possible.

Nickel-based systems have higher energy density, lower cost, and longer cycle life than the cobalt-based cells but they have a slightly lower voltage.

New electrolytes and additives enable charging to 4.4V/cell and higher to boost capacity.

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.

its lower nominal voltage of 3.2V/cell reduces the specific energy below that of cobalt-blended lithium-ion. With most batteries, cold temperature reduces performance and elevated storage temperature shortens the service life, and Li-phosphate is no exception. Li-phosphate has a higher self-discharge than other Li-ion batteries, which can cause balancing issues with aging.

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.

Lithium Titanate (Li2TiO3) — LTO

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. Li-titanate is safe, has excellent low-temperature discharge characteristics and obtains a capacity of 80 percent at –30°C (–22°F).

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.

	Lithium cobalt oxide(LCO)	Lithium Manganese Oxide(LMO)	Lithium Nickel Manganese Cobalt Oxide(NMC)	Litium Iron Phospate(LFP)	Lithium Nickel colbalt Aluminium Oxide(NCA)	Lithium Titanium Oxide(LTO)
Chemical Formula	`LiCoO_2`	`LiMn_2O_4`	`LiNiMnCoO_2`	`LiFePO_4`	`LiNiCoAlO_2`	`LiTiO_3`
Anode Material	Graphite carbon	Graphite carbon	Graphite carbon	Graphite carbon	Graphite carbon	Lithium Titanium Oxide
Cathode Material	Lithium Cobalt Oxide	Lithium Manganese Oxide at 350 degrees	Lithium nickel manganese cobalt oxide	Lithium Iron Phosphate	Lithium Nickel Cobalt Aluminium oxide	Lithium Manganese Oxide or NMC
Electrolyte	Lithium salt in an organic solvent	Lithium halide dissolved in an organic solvent	Lithium salt in an organic solvent	Lithium salt in an organic solvent	Lithium salt in an organic solvent	Lithium salt in an organic solvent
Anode Reaction	Charging(L to R) and Discharging (R to L) `6C+xe^-+xLi^+harrLi_xC6`	Charging(L to R) and Discharging (R to L) `xLi^++xe^-)+6CharrLi_xC_6`	Charging(L to R) and Discharging (R to L) `xLi^++xe^-)+nCharrLi_xC_n`	Charging(L to R) and Discharging (R to L) `xLi^++xe^-+6CharrLi_2C_6`	Charging(L to R) and Discharging (R to L) `xLi^++xe^-+6CharrLi_xC_6`	Charging(L to R) and Discharging (R to L) `Ti5O12+4Li^++4e^-harrLi_4Ti_5O_12`
Cathode Reaction	`LiCoO_2harrLi_(1-x)CoO_2+xLi^++xe^-`	`LiMnO_2harrLi_(1-x)Mn2O4+xLi^++xe^-`	`LiMO_2harrLi(1-x)MO_2+xLi^++xe^-`	`LiFeePO_4harrLi(1-x)FePO_4+xLi^++xe^-`	`LiNiCoAlO_2harrLi_(1-x)NiCoAlO_2+xLi^++xe^-`	`4LiMn_2O_4harr4Mn_2O_4+4Li^++4e^-`
Overall Reaction	`LiCoO_2+6CharrCoO_2+LiC_6`	`LiMn_2O_4+6CharrLiC_6+Mn_2O_4`	`Li_(1-x)MO2+Li_XC_nharrLiMO_2+nC`	`LiFePO_4+6CharrLiC_6+FePO_4`	`6C+LiNiCoAlO_2harrLiC_6+NiCoAlO_2`	`Li_4Ti_5O_12+4Mn_2O_4harr4LiMn_2O_4+Ti_5O_12`

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

LCO

LMO

NMC

LFP

NCA

LTO

compares the specific energy of lead-, nickel- and lithium-based systems. While Li-aluminum (NCA) is the clear winner by storing more capacity than other systems, this only applies to specific energy.

In terms of specific power and thermal stability, Li-manganese (LMO) and Li-phosphate (LFP) are superior. Li-titanate (LTO) may have low capacity but this chemistry outlives most other batteries in terms of life span and also has the best cold temperature performance.

Moving towards the electric powertrain, safety and cycle life will gain dominance over capacity. (LCO stands for Li-cobalt, the original Li-ion.)

Specific Energy of Lead, Nickel and Lithium Based Batteries.