Week 1 Understanding Different Battery Chemistry

Battery:- A Battery is a device that is able to store electrical energy in the form of chemical energy and convert that energy into electricity.

Lithium ion battery :- These are the batteries that function based on the transfer of the lithium ions between a cathode and an anode. Lithium ion batteries are the batteries with higher specific energies than batteries made from other materials such as zinc and lead due to the relatively light weight and low density of lithium.They are also more stable due to their small radii of lithium ions.

There are two main categories of Lithium ion batteries : primary (single-use) and secondary (rechargeable).

S.No	Battery type	Electrode material	Chemical Reaction
1	LCO	Cathode : Lithium cobalt oxide(LiCoO2) Anode : Graphite	At Anode: LiC6 --) Li+ + e- + C6   At Cathode:CoO2 + Li+ + e-  --) LiCO2 Complete : LiC6 + CoO2 --) C6 + LiCoO2
2	LMO	Cathode: Lithium manganeseoxide (LiMn2O4)  Anode : Graphite	At Anode: LiC6 --) Li+ + e- + C6 At Cathode: Mn2O4 + Li+ + e- --) LiMn2O4 Complete : LiC6 + Mn2O4 --) C6 + LiMn2O4
3	NCA	Cathode : Lithium Nickel Cobalt Alluminium oxide (LiNiCoAlO2) Anode : Graphite	At Anode : LiC6 --) Li+ + e- + C6 AT Cathode : NiCoAlO2 + Li+ + e- --) LiNiCoAlO2 Complete : LiC6 + NiCoAlO2 --) C6 + LiNiCoAlO2
4	NMC	Cathode : Lithium Nickel Manganese Cobalt oxide(LiNiMnCoO2) Anode : Graphite	At Anode : LiC6 --) Li+ + e- + C6 At Cathode : NiMnCoO2 + Li+ + e- --) LiNiMnCoO2 complete : LiC6 + NiMnCoO2 --) C6 + LiNiMnCoO2
5	LFP	Cathode : Lithoum iron phosphate(LiFePO4)  Anode : Graphite	At Anode : LiC6 --) Li+ + e- + C6 At Cathode : FePO4 + Li+ + e- --) LiFePO4 Complete : LiC6 + FePO4 --) C6 + LiFePO4
6	LTO	Cathode : Lithium Manganese oxide (LiMn2O4)   Anode : Lithium titanate (Li2TiO3)	At Anode: Li2TiO3 --) TiO3 + 2Li+ + 2e- At Cathode: Mn2O4 + 2Li+ + 2e- --) LiMn2O4 Complete : Li2TiO3 + 2Mn2O4 --) 2LiMn2O4 + TiO3

Li-ion batteries consist of largely four main components: cathode, anode, electrolyte and separator.Every single component of a Li-ion battery is essential as it can't function when one of the components is missing.

"Cathode": It determines the capacity and voltage of a Li-ion battery. A lithium ion battery generates electricity through chemical reactions of lithium. Lithium is inserted into the battery and that space for lithium is called cathode. However since lithium is unstable in the element form, the combination of Lithium and oxygen, lithium oxide is used for cathode. The material that intervenes the electrode reaction of the actual battery just like lithium oxide is called"active material". In other words, in the cathode of a Li-ion battery, lithium oxide is used as an active material. 

"Anode": It sends electrons through a wire. Just like cathode, the anode substrate is also coated with active material. It enables electric current to flow through the external circuit while allowing reversible absorption/ emission of lithium ions released from the cathode. While charging, the lithium ions are stored in the anode and not the cathode.

"Electrolyte": It allows the movement of ions only. Lithium ions move through the electrolyte and electrons move through the wire. This is the key principle in enabling the use of electricity in a battery.If ions flow through the electrolyte safety will be jeopardized. Electrolyte serves as the medium that enables the movement of lithium ions between the cathode and the anode. The electrolyte is composed of salts, solvents and additives.

"Separator" : Barrier between cathode and anode. The cathode and anode determines the performance of a battery while the electrolyte and separator determine the safety of a battery. It prevents the direct flow of electrons and carefully let's only the ions pass through the internal microscopic hole. Commercialized separators we have today are synthetic resin such as polyethylene (PE) and polypropylene(PP)

Comparison of different Li-ion batteries in the basis of characteristics:

Battery type	Voltage	Specific energy	C-rate(charge)	C-rate(discharge)	Cycle	Thermal runaway
LCO	3.60V nominal; typical operating range 3-4.2V/cell	150-200 Wh/kg. Speciality cross provide upto 240Wh/kg.	0.7-1C, charges to 4.2V(most cells); 3h charge typical. Charge current above 1C shortens battery life.	1C; 2.5V cut off. Discharge current above 1C shortens battery life.	500-1000, related to depth of discharge, load, temperature	150°C (302°F). Full charge promotes thermal runaway
LMO	3.7V nominal, typical operating range 3 - 4.2V/cell	100-150Wh/kg	0.7-1C typical,3C maximum,charges to 4.2V(most cells)	1C;10C possible with some cells,30C pulse(5s),2.5V cut-off	300-700(related to depth of discharge and temperature)	250°C(482°F)typical.High charge promotes thermal runaway.
NMC	3.6V,3.7V nominal, typical operating range 3-4.2V/cell or higher	150-220Wh/kg	0.7-1C, charges to 4.2V, some go to 4.3V ; 3h charge typical. Charge current above 1C shortens battery life.	1C; 2C possible on some cells 2.5V cut-off.	1000-2000 (related to depth of discharge and temperature)	210°C(410°F)typical.High charge promotes thermal runaway.
LFP	3.2,3.3V nominal, typical operating range 2.5-3.65V/cell	90-120Wh/kg	1C typical,charges to 3.65V;3h charge time typical	1C, 25C on same cells 40 A pulse(2s) 2.5V cut-off(lower the 2V causes damage)	2000 and higher (related to depth of discharge and temperature)	270°C(518°F) Very safe battery even if fully charged
NCA	3.6V nominal,typical operating range 3-4.2V/cell	200-260Wh/kg  300Wh/kg   predictable	0.7C,charges to 4.2V (most cells) 3h charge typical, fast charge possible with some cells	1C typical, 3V cut-off, high discharge rate shortens battery life	500(related to depth of discharge and temperature)	150°C(302°F)typical,high charge promotes thermal runaway
LTO	2.4V nominal,typical operating range  1.8-2.85V/cell	50-80Wh/kg	1C typical,5C maximum,charges to 2.85V	10C possible,30C 5s pulse,1.8V cut-off on LCO/LTO	3000-7000	One of safest lithium ion batteries.