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.

Name	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)
Anode Material	Graphite	Graphite	Graphite	Graphite	Graphite	Graphite
Cathod Material	Lithium Cobalt Oxide	Lithium Manganese	Nickel Cobalt aluminum	Nickel Manganese	Lithium Iron Phosphate	Lithium Titanate
Anode reaction	`LiC_6<- >C_6+Li^++e^+`	`LiC_6<- >C_6+Li^++e^+`	`LiC_6<- >C_6+Li^++e^+`	`LiC_6<- >C_6+Li^++e^+`	`LiC_6<- >C_6+Li^++e^+`	`Li_4Ti_3O_12++Ti_5O_12+4Li^++4e^-`
Cathod Reaction	`CoO2+Li^++(e^-)<->LiCoO2`	`MnO_2 + Li^+ + (e^-) <-> LiMnO_2`	`NiCoAlO_2 + Li^+(e^-) <-> LiNiCoAlO_2`	`NiMnCoO_+ Li^+ +(e^-) <>LiNiMnCoO_2`	`FePO_4+Li^+ + (e^-) <-> LiFePO_4`	`4Mn_2O_4Li^+ + 4e^- <-> 4LiMn_2O_4`
Chemical Reaction	`C_6+LiCoO_2 <-> LiC_6+CoO_2`	`C6+LiMn_2O_4 <-> LiC_4 + Mn_2O_4`	`C_6+LiNiCoAlO_2 <-> LiC_4+NiCoAlO_2`	`C_6+LiNiMnCoO_2 <-> LiC_6 + NiMnCoO_2`	`C_6+LiFePo_4 <-> LiC_4+FePO_4`	`4Mn_2O_4 + Li_4Ti_5O_12<-> 4LiMn_2O_4 + Ti_5O_12`

Lithium Cobalt Oxide(LCO) LiCoO₂ -

• Voltages: - 3.60V nominal; typical operating range 3.0–4.2V/cell,
• Specific energy (capacity):-150–200Wh/kg. Specialty cells provide up to 240Wh/kg.
• Cycle life:- 500–1000, related to depth of discharge, load, temperature.
• Charge (C-rate) :-0.7–1C, charges to 4.20V (most cells); 3h charge typical. Charge current above 1C shortens battery life.
• Discharge (C-rate):-1C; 2.50V cut off. Discharge current above 1C shortens battery life.
• Cycle life : - 500–1000, related to depth of discharge, load, temperature
• Thermal runaway : - 150°C (302°F). Full charge promotes thermal runaway.

• Anode Material & Reaction : - Graphite `LiC_6<- >C_6+Li^++e^+`

  Cathod Material & Reaction :- LCO or Li-Cobalt Oxide(~60% Co) `CoO2+Li^++(e^-)<->LiCoO2`

  Chemical Reactions :- `C_6+LiCoO_2 <-> LiC_6+CoO_2`

• Applications:-Mobile phones, tablets, laptops, cameras.

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.

Lithium Manganese Oxide (LMO) LiMn₂O₄ -

• Voltages:- 3.70V (3.80V) nominal; typical operating range 3.0–4.2V/cell.
• Specific energy (capacity):- 100–150Wh/kg
• Charge (C-rate):-0.7–1C typical, 3C maximum, charges to 4.20V (most cells)
• Discharge (C-rate):- 1C; 10C possible with some cells, 30C pulse (5s), 2.50V cut-off
• Cycle life:- 300–700 (related to depth of discharge, temperature)
• Thermal runaway:- 250°C (482°F) typical. High charge promotes thermal runaway.

• Anode Material & Reaction : - Graphite `LiC_6<- >C_6+Li^++e^+`

  Cathod Material & Reaction :- LMO or Li-Manganese Oxide (Spinel structure) `MnO_2 + Li^+ + (e^-) <-> LiMnO_2`

  Chemical Reactions :- `C6+LiMn_2O_4 <-> LiC_4 + Mn_2O_4`

• Applications :- Power tools, medical devices, electric powertrains.

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.

spider web of a typical Li-manganese battery. The characteristics appear marginal but newer designs have improved in terms of specific power, safety and life span. Pure Li-manganese batteries are no longer common today; they may only be used for special applications.

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 Cobalt Aluminum Oxide (NCA) LiNiCoAlO₂ -

• Voltages:- 3.60V nominal; typical operating range 3.0–4.2V/cell
• Specific energy (capacity):- 200-260Wh/kg; 300Wh/kg predictable
• Charge (C-rate):- 0.7C, charges to 4.20V (most cells), 3h charge typical, fast charge possible with some cells
• Discharge (C-rate):- 1C typical; 3.00V cut-off; high discharge rate shortens battery life
• Cycle life:- 500 (related to depth of discharge, temperature)
• Thermal runaway:- 150°C (302°F) typical, High charge promotes thermal runaway

• Anode Material & Reaction : - Graphite `LiC_6<- >C_6+Li^++e^+`

  Cathod Material & Reaction :- NCA or Li-Aluminum`NiCoAlO_2 + Li^+(e^-) <-> LiNiCoAlO_2`

  Chemical Reactions :- `C_6+LiNiCoAlO_2 <-> LiC_4+NiCoAlO_2`

• Applications :- Medical devices, industrial, electric powertrain (Tesla).

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. Figure Idicates that six key characteristics. 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.

NCA is a further development of lithium nickel oxide; adding aluminum gives the chemistry greater stability.

Lithium Nickel Manganese Cobalt Oxide (NMC) LiNiMnCoO₂ -

Short form: NMC (NCM, CMN, CNM, MNC, MCN similar with different metal combinations) Since 2008

• Voltages:- 3.60V, 3.70V nominal; typical operating range 3.0–4.2V/cell, or higher
• Specific energy (capacity):- 150–220Wh/kg
• Charge (C-rate):- 0.7–1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge current above 1C shortens battery life
• Discharge (C-rate):- 1C; 2C possible on some cells; 2.50V cut-off
• Cycle life:- 1000–2000 (related to depth of discharge, temperature)
• Thermal runaway:- 210°C (410°F) typical. High charge promotes thermal runaway

• Anode Material & Reaction : - Graphite `LiC_6<- >C_6+Li^++e^+`

  Cathod Material & Reaction :- Nickel Manganese Cobalt Oxide `NiMnCoO_+ Li^+ +(e^-) <>LiNiMnCoO_2`

  Chemical Reactions :- `C_6+LiNiMnCoO_2 <-> LiC_6 + NiMnCoO_2`

• Applications :- E-bikes, medical devices, EVs, industrial.

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. A silicon-based anode will go to 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.

Battery manufacturers move away from cobalt systems toward nickel cathodes because of the high cost of cobalt. 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. This battery is the preferred candidate for the electric vehicle and has the lowest self-heating rate.

There is a move towards NMC-blended Li-ion as the system can be built economically and it achieves a good performance. The three active materials of nickel, manganese and cobalt can easily be blended to suit a wide range of applications for automotive and energy storage systems (EES) that need frequent cycling. The NMC family is growing in its diversity.

Lithium Iron Phosphate (LFP) LiFePO₄ -

• Voltages:- 3.20, 3.30V nominal; typical operating range 2.5–3.65V/cell
• Specific energy (capacity):- 90–120Wh/kg
• Charge (C-rate):- 1C typical, charges to 3.65V; 3h charge time typical
• Discharge (C-rate):- 1C, 25C on some cells; 40A pulse (2s); 2.50V cut-off (lower that 2V causes damage)
• Cycle life:- 2000 and higher (related to depth of discharge, temperature)
• Thermal runaway:- 270°C (518°F) Very safe battery even if fully charged

• Anode Material & Reaction : - Graphite `LiC_6<- >C_6+Li^++e^+`

  Cathod Material & Reaction :- Iron Phosphate `FePO_4+Li^+ + (e^-) <-> LiFePO_4`

  Chemical Reactions :- `C_6+LiFePo_4 <-> LiC_4+FePO_4`

• Applications :- Portable and stationary needing high load currents and endurance.

In 1996, the University of Texas (and other contributors) discovered phosphate as cathode material for rechargeable lithium batteries. 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. 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. This can be mitigated by buying high quality cells and/or using sophisticated control electronics, both of which increase the cost of the pack. Cleanliness in manufacturing is of importance for longevity. There is no tolerance for moisture, lest the battery will only deliver 50 cycles.

With four Li-phosphate cells in series, each cell tops at 3.60V, which is the correct full-charge voltage. At this point, the charge should be disconnected but the topping charge continues while driving. Li-phosphate is tolerant to some overcharge; however, keeping the voltage at 14.40V for a prolonged time, as most vehicles do on a long road trip, could stress Li-phosphate. Time will tell how durable Li-Phosphate will be as a lead acid replacement with a regular vehicle charging system. Cold temperature also reduces performance of Li-ion and this could affect the cranking ability in extreme cases.

Li-phosphate has excellent safety and long life span but moderate specific energy and elevated self-discharge

Lithium Titanate (LTO) - Li2TiO3

• Cathode = ; Anode = Li2TiO3 (titanate)
  Short form: LTO or Li-titanate Commercially available since about 2008.
• Voltages:- 2.40V nominal; typical operating range 1.8–2.85V/cell
• Specific energy (capacity):- 50–80Wh/kg
• Charge (C-rate):- 1C typical; 5C maximum, charges to 2.85V
• Discharge (C-rate):- 10C possible, 30C 5s pulse; 1.80V cut-off on LCO/LTO
• Cycle life:- 3,000–7,000
• Anode Material & Reaction : - Titanate `Li_4Ti_3O_12++Ti_5O_12+4Li^++4e^-`
• Cathod Material & Reaction :- Lithium manganese oxide or NMC `4Mn_2O_4Li^+ + 4(e^-) <-> 4LiMn_2O_4`
• Chemical Reactions :- `4Mn_2O_4 + Li_4Ti_5O_12<-> 4LiMn_2O_4 + Ti_5O_12`
• Thermal runaway:- One of safest Li-ion batteries
• Applications :- UPS, electric powertrain (Mitsubishi i-MiEV, Honda Fit EV), solar-powered street lighting.

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 (–22°F).

LTO (commonly Li4Ti₅O₁₂) has advantages over the conventional cobalt-blended Li-ion with graphite anode by attaining zero-strain property, no SEI 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. At only 65Wh/kg, the specific energy is low, rivalling that of NiCd. Li-titanate charges to 2.80V/cell, and the end of discharge is 1.80V/cell. the Li-titanate battery. Typical uses are electric powertrains, UPS and solar-powered street lighting.

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