Week 1 Understanding Different Battery Chemistry

PROBLEM:

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

SOLUTION:

Discussing about different Lithium batteries in details,

1. Lithium Cobalt Oxide (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 drawback of Li-cobalt is a relatively short life span, low thermal stability, and limited load capabilities (specific power)

CHEMICAL REACTION:

At Anode:

LiC₆ → xLi⁺+xe⁻+ C₆

At Cathode:

Li_1−xCoO₂ + xLi⁺ + xe^- → LiCoO₂

Overall Reaction:

C₆+LiCoO₂↔Li_xC₆+Li₁−_xCoO₂

2. Lithium Manganese Oxide (LMO)

• 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.
• Another added advantage of spinel is high thermal stability and enhanced safety,
• The cycle and calendar life is limited for LMO batteries.

CHEMICAL REACTION:

At Anode:

Li → Li⁺ + e⁻

At Cathode:

Mn₂O₄ + Li⁺ + e⁻ → LiMn₂O₄

Overall reaction:

Li + MnO₂ → LiMnO₂

3. Lithium Nickel Manganese Cobalt Oxide (NMC)

• Similar to Li-manganese, these systems can be tailored to serve as Energy Cells or Power Cells.
• 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.

CHEMICAL REACTION:

At Anode:

Li_xC_n → nC + xLi⁺ + xe⁻

At Cathode:

Li_1−xMO₂ + xLi⁺ + xe⁻ → LiMO₂

Redox Reaction:

Li_1−xMO₂ + Li_xC_n → LiMO₂ + nC

4. Lithium Iron Phosphate (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 hold good thermal stability, enhanced safety.

CHEMICAL REACTION:

At Anode:

LiC₆ → Li⁺ + e⁻ + C₆

At Cathode:

LiFe(III)PO₄ + xLi⁺ + xe⁻ → LiFe(II)PO₄FePO4 + Li⁺ + e⁻ → LiFePO₄

Overall Reaction:

LiFePO₄ + 6C → LiC₆ + FePO₄

5. Lithium Nickel Cobalt Aluminium Oxide (NCA)

• NCA 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.

CHEMICAL REACTION:

At anode:

C₆Li → 6C + Li⁺ + e^-

At cathode:

NiCoAlO₂ + Li⁺ + e^- → LiNiCoAlO₂

Overall reaction:

C₆Li + NiCoAlO₂ → Li_1-xNiCoAlO₂ + Li_xC₆

6. Lithium Titanium Oxide (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.
• 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 efficiency of 80 percent at –30°C (–22°F).

CHEMICAL REACTION:

At anode:

Li₇Ti₅O₁₂ → Ti₁₅O₁₂ + 4Li + 4e^-

At cathode:

4Li_1-xMn₂O₄ + 4Li + 4e^- → 4LiMn₂O₄

Overall reaction:

Li₇Ti₅O₁₂ + 4Mn₂O₄ → 4LiMn₂O₄ + Ti₅O₁₂

PROBLEM:

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

SOLUTION:

COMPARISON-1:

• Based on 0-4, 0 being low and 4 being highest. (ie. Safety -1 : Less safe, Lifespan-4: Highly durable)

COMPARISON-2:

COMPARISON-3:

LEARNING OUTCOME

• We have learned about different types of lithium-ion batteries and the reactions happening in them.
• Li-ion is going to be widely used in future technologies due to its wide range of applications.