Week 1 Understanding Different Battery Chemistry

The Lithium ion batteries are constructed of below MoC

Anode materials are majorly:-

1. Anode materials are made up of
   1. Layered transition metal oxides , spinel and olivines
   2. Metal oxides chemistries are NCA, NMC and LCO
   3. Spinels are high power density but poor electronic conductivity and structural stability ( LMO and LTO )
   4. Olivines are good for better safety and long life span but they have their challenges with low capacity and voltage ( LiFePO4)

2. Cathode materials are made up of
   1. Carbon based anode: graphite and hard carbon
   2. Low cost, stable and high specific capacity
   3. The issue is of lithium plating. This happens when the potential of anode becomes excessively low li ions can plate out as metallic lithium on the surface of anode
   4. The plate out can result into dendrite formation and reduction in the capacity
3. The electrolyte is made up of
   1. Organic solvents such as ethylene carbonate , dimethyl carbonate ,and propylene carbonate which contains dissolved lithium salt
   2. For carbon anodes operating at a potential close to the plating of lithium, this causes the reduction of electrolytes at the anode, building a protective coating known as SEI layer. This SEI is formed during initial charge cycle
   3. The challenge lies with sub zero temperature. In the sub-zero temperature transport properties suffer which drastically lowers cell performance and efficiency. Heaters are introduced to take care of this issue

Type of Cathode	Cost	Specific Power	Specific Energy	Safety	Performance	Life span
Lithium Cobalt Oxide	Low	Low	High	Low	Medium	Low
NCA ( Litihium cobalt Aluminium)	Medium	Medium	High	Medium	Medium	Medium
NMC ( Lithium Nickel Mangenese cobalt )	Low	Medium	High	Medium	Medium	Medium
LMO ( Lithium Mangenese Spinel )	Low	Medium	Medium	Medium	Low	Low
LTO ( Lithium Titanate)	High	Medium	Low	High	High	High
LFP ( Lithium Phosphate )	Low	High	Low	High	Medium	High

Lithium Ion Cell elements

1. Anode , cathode, electrolyte, separator and casing
2. Choice of materials for electrodes
3. The majority of manufacturers use graphite carbon anode
4. Separator which physically isolates the positive and negative electrode
5. It is an ionic conductor but an electronic insulator
6. It also prevents internal short circuiting between two electrodes
7. Current collectors are electronic conductors with which the electrodes are mixed

The chemical reactions happening in a LiB batteries are as below:-

1. During the charging negative electrode accepts electrons and gets reduced
2. While discharging negative electrode gives up electrons and gets oxidized. The positive charged ions or cations move through the electrolyte towards the positive electrode and negatively charged ions or anions move through the electrolyte towards the negative electrode
3. The Lithium ion batteries operate by shuttling Li+ ions to the anode host structure on charge