Week 1 Understanding Different Battery Chemistry
Alm:
*To make a study and understand about the electrochemistry of different types of lithium ion calls
Questions:
1. Prepare a table which includes materials & chemical reactions occurring at the anode and cathode of ICO. LMC), NCA, NMC, LFP and LTO type of lithlum ion cells.
Battery:
4
*A Battery is a device consisting of one or more electrochemical cells with external connections for powering electrical devices such as Flashlights, mobile phones and electric cars.
anode.
* When a battery is supplying electric power, its positive terminal is the cathode and its negative terminal is the
• The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal.
* When a battery is connected to an external electric load, a Redox reaction converts high-energy reactants to lower-energy products, and the free energy difference is delivered to the external circuit as electrical energy.
There are two types of batteries,
1. Primary cell - These batteries are one time use batteries and they cannot be recharged for further usage
2. Secondart cell - These batteries can be recharged and can be used for multiple times.
Lithium ion Cell:
The Lithium lon batteries are secondary type of batteries which can be recharged for further usage
The Lithium ion cells have four main Components in it and they are,
(1) Cathode
(i) Anode:
(1) Electrolyte
(iv) Seperator
(1) Cathode:
They are the positive elctrodes of the cell.
The cathode elctrode is usually made up of,
1 Layered Transition metal oxides-Has high Capacity but high in cost and poor in safety.
2. Spinels -High power Density but poor in conductivity and stability. 3 Olivines - Lees capacity but has long life and are high in safety.
(ii) Anode:
They are the negative elctrodes of the cell.
The anode elctrode is usually made up of
Related C
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1. Graphite
2 Hard Carbon, these anodes are less in cost and high in stability and specific capacity.
(iii) Electrolyte:
An electrolyte is a substance that produces on electrically conducting solution when dissolved in a polar solvent
The dissolved electrolyte separates into cations and anions, which disperse uniformly through the solvent
Generally Lithium ion cells have electrolyes of Organic solvents such as, Ethylene carbonate, dimethyl carbonate,
propylene carbonate and lithium salt as solute,
(iv) Seperator:
Battery separators provide a barrier between the anode (negative) and the cathode (positive) while enabling the exchange of lithium ions from one side to the other.
Working Principle:
In a lithium-ion battery, lithium atoms at the anode (-ve) split. This makes electrons and lithium ions (lithium atoms with a positive charge). The lithium ions move within the battery to the cathode (+ve) through an electrolyte. Electrons generally can't pass through this material. So the electrons take a different path to the cathode through an external circuit. That creates an electric current that can power a device. At the cathode, the electrons meet up with the lithium ions for another chemical reaction.
To charge a battery, this process runs in reverse. The ions and electrons journey back to the anode. In a lithium-ion battery, that anode usually is graphite. The lithium ions tuck between the atom-thin layers of the graphite. The cathode can be one of several lithium-containing materials.
Types of Li-ion Battery
1) Lithium Cobalt Oxide (LiC002) - LCO
2) Lithium Manganese Oxide (LiMn204) - LMO
3) Lithium Nickel Manganese Cobalt Oxide (LiNiMnC002) - NMC
4) Lithium Iron Phosphate (LiFePO4) - LFP
5) Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAl02) — NCA -
6) Lithium Titanate (Li2TiO3) - LTO
1) Lithium Cobalt Oxide (LiC002) - LCO
DURING DISCHARGE
At the anode, lithium is oxidised. Lithium ions are released from the carbon, along with electrons:
At the cathode, lithium-ions are absorbed by the lithium dioxide, and the electrode is reduced as it also receives the electrons from the circuit:
LiCoO₂+aLi + ze¨ → LiCoO₂
The overall reaction is:
C + LiCoO, + L_C+Li, CoO,
2) Lithium Manganese Oxide (LiMn204) - LMO
Reaction at anode : Lili+ + e
Reaction at cathode: Mno2+ LI++ e- MnOOLI
3) Lithium Nickel Manganese
Positive Elektrode (NMC)
Cobalt Oxide (LiNiMnC002) - NMC
Negative Elektrode (Graphit)
4) Lithium Iron Phosphate (LiFePO4) - LFP
DURING DISCHARGE
At the anode, lithium is oxidised. Lithium ions are released from the carbon, along with electrons:
LiC6 → Lit + e + Co
At the cathode, lithium ions are absorbed by the lithium dioxide, and the electrode is reduced as it also receives the electrons from the circuit:
LiFe(III)PO+zLi + ze → LiFe(II) PO
FePO4 + Lit + e → LiFePO4
The overall reaction is:
LiFePO4 +6C LiCs + FePO4
5.Lithium Nickel Cobalt Aluminum Oxide (LINICOAIO2) - NCA
LisCoO₂ → 1/2LiCoO₂ + 1/6Co³O + 1/60₂ Li-NiO₂ →→ (1 − 2x)LiNiO₂ + xLiNi₂O (x ≤ 0.5) Li) NiO₂ → [Li(1–x)Ni (2x−1)/3] [Ni(4–2x)/3]Q8-4x)/3 + (2x − 1)/3Q, (x>0.5) Li-NiO₂ → (2 − x)Li(1-x)/(2-x)Ni1/(2-x)O + x/20₂