Week 1 Understanding Different Battery Chemistry

LCO

Lithium Cobalt Oxide

Graphite

`LiC_6 harr C_6 + Li^+ + e^+`

Cobalt Oxide

`CoO_2 + Li^+ + e^+ harr LiCoO_2`

While charging(left to right), Anode loses Li_+ ions which travels to cathode through electrolyte and combines with the Cobalt Oxide to give LiCoO_2. Electrons from anode move to cathode through external circuit.

While discharge, the reverse process happens where the Li_+ ions are removed from cathode structure and move to anode to combine with graphite while electrons move through external circuit.

LMO

Lithium Manganese Oxide

Graphite

`LiC_6 harr C_6 + Li^+ + e^+`

Manganese Oxide

`Mn_2O_4 + Li^+ + e^+ harr LiMn_2O_4`

While charging(left to right), Anode loses Li_+ and e_- ions from graphite layers which travels to cathode through electrolyte and external circuit seperately to combine with the Manganese Oxide to give LiMn_2O_4.

While discharge, the reverse process happens where the Li_+ and e_- ions seperate from cathode structure and move to anode to intercalacte as Li atoms among the carbon layers.

NCA

Lithium Nickel Cobalt Aluminium Oxide

Graphite

`LiC_6 harr C_6 + Li^+ + e^+`

Nickel Cobalt Alumininum Oxide

`NiCoAlO_2 + Li^+ + e^+ harr LiNiAlCoO_2`

Same situation as above where the anode reactions are same (graphite) and cathode is replaced by Nickel Cobalt Alumnium Oxide. Anode loses Lithium atoms while charging and gains them while discharging.

NMC

Lithium Nickel Manganese Cobalt Oxide

Graphite

`LiC_6 harr C_6 + Li^+ + e^+`

Nickel Manganese Cobalt Oxide

`NiMnCoO_2 + Li^+ + e^+ harr LiNiMnCoO_2`

Same situation as above where the anode reactions are same (graphite) and cathode is replaced by Nickel Manganese Cobalt Oxide. Anode loses Lithium atoms while charging and gains them while discharging.

LFP

Lithium Iron Phosphate

Graphite

`LiC_6 harr C_6 + Li^+ + e^+`

Iron Phosphate

`FePO_4 + Li^+ + e^+ harr LiFePO_4`

Same situation as above where the anode reactions are same (graphite) and cathode is replaced by Iron phosphate that accepts and hold Lithium atoms while charging (reduction) and loses Li atoms (oxidation) to anode while discharging.

LTO

Lithium Titatnate

Titanate `Li_2TiO_3`

`Li_2TiO_3 harr TiO_3 + 2Li^+ + 2e^+`

Manganese Oxide

`Mn_2O_4 + Li^+ + e^+ harr LiMn_2O_4`

While charging, Lithium Titanate at the anode disintegrates to form Titanate oxide and Li_+ ions. These Li ions travel towards cathode to form LiMn_2O_4 just like in LMO cells. While discharge, they lose Li atoms to anode(oxidation).

LCO

Lithium Cobalt Oxide

• High specific energy - Suitable for consumer electronics
• Low thermal stability
• Less power output
• Cobalt is expensive. Thus NMC and NCA is more preferred.
• Relatively short life span - because of SEI and lithium plating while fast charging/charging at low temperature

LMO

Lithium Manganese Oxide

• 3D spinal structure
  • Low internal cell resisance enables fast charging & high current discharge
  • High thermal stability & enhanced safety
• Low cycle & calendar life
• Moderate in overall performance
• Newer designs - Offer improvements in specific power, safetyand lifespan (Ex. wih NMC)
• Applications -
  • power tools
  • medical instruments
  • EVs and HEVs

NCA

Lithium Nickel Cobalt Aluminium Oxide

• Adding aluminum gives the chemistry greater stability
• High specific energy, good specific power with long life span - great for EV powertrains
• Cons - High cost and marginal safety

NMC

Lithium Nickel Manganese Cobalt Oxide

• Nickel - high specific energy but poor stability
• Manganese - spinel structure gives good thermal sability but low specific energy
• Cobalt - expensive, stabilises Nickel
• Serve as energy cells or power cells, has good secific energy and overall performance
• Applications-
  • Power tools
  • electric powertrains (ebikes etc)
  • ESS

LFP

Lithium Iron Phosphate

• Nano-scale phosphate cathode material -
  • High current rating, long cycle life
  • Good thermal stability, safety, abuse tolerance
• Cons -
  • Higher self discharge rate
  • Low temperature performance
  • Shortened life at higher temperature
• Applications-
  • Starter battery, ESS

LTO

Lithium Titatnate

• LTO replaces the graphite in anode of a typical Li-ion battery. Cathode - LMO or NMC
• Pros -
  • Fast charging, high discharge current (10C), high cycle count, safe at low temp. discharge
  • No SEI film formation and no lithium plating while fast charging/charging at low temperature
  • Comparatively better thermal stability at high temperature
• Cons -
  • Expensive, low specific energy
• Applications -
  • EV, UPS, solar powered street lighting