Week 1 Understanding Different Battery Chemistry

Ans: 1,2

In a lithium-ion battery cell, both electrodes depend on an intercalation mechanism rather than a standard redox chemical reaction.Essentially all commercial lithium-ion battery cells use some form of graphite for their negative electrodes. Graphite is very common.However, the bonding between one layer of graphene and its neighboring layer is quite weak and this is why graphite is used in pencils. Graphite is used in probably every commercial lithium-ion cell on the market; not every, almost every lithium-ion battery cell that's used in the market. But there are other materials that could be used as well. And one other material that has some interesting properties is lithium titanate oxide or LTO. The titanium and oxygen atoms are very tightly bonded into this crystalline structure so that these bonds are not disturbed when lithium enters or leaves the particle. the lithium-ion battery cells are made using electrolytes that are non-aqueous and they are built using organic solvents plus a lithium-based salt that dissolves into that solvent. The electrolyte in a lithium-ion battery cell acts purely as an ion conductor. It does not take part of the normal chemical reactions for charging and discharging the battery cell.These include ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. The separator is a permeable membrane that has tiny holes in it and these holes are large enough that ions can pass through them, but they're also small enough that the positive and negative electrode can't touch each other. If they were to touch each other, you would have a short circuit which would lead to heat buildup and thermal runaway, possibly a fire or an explosion. For this reason, the separator also must be an electronic insulator, we can't allowed electrons to flow across the separator but we want ions to flow very easily through the porous in the separator.

LCO(Lithium Cobalt Oxide):

Anode: Graphite(C6)

Cathode: Lithium Cobalt Oxide (LiCoO2)

Positive Elctrode(Cathode) Half-reaction in Lithium doped cobalt oxide subtrate

CoO2+Li(+) +e(-) ------->LiCoO2

Negative Elctrode (Anode) Half reaction for graphite is

LiC6 ------->C6 +Li(+) + e(-)

The Full Reaction (Left :charged, Right :Discharged) being:

Lic6+CoO2< ------->C6+LiCoO2

Nominal Voltage :3.7V

Full Voltage :4.2V

Cycle Life : 500-1000 Cycles

Specific energy(capacity):150-200 wh/kg

Applications: Cell Phones ,Laptops,Cameras

LMO(Lithium Manganese Oxide):

Anode:Graphite(C6)

Cathode:LiMnO2(treated at 350 degree C)

Electrolyte:Lithium Halide Dissolved in Organic solven

at Anode:Mn2O4+Li(+) +e(-) ------->LiMn2O4

at Cathode:LiC6 ------->C6 +Li(+) + e(-)

The Full Reaction (Left :charged, Right :Discharged) being:

Lic6+Mn2O4< ------->C6+LiMn2O4

Nominal Voltage :3.7V

Full Voltage :3..8V

Cycle Life : 300-700 Cycles

Specific energy(capacity):100-150 wh/kg

LFP(Lithium Iron Phosphate):

Anode:Graphite(C6)

Cathode:LiFePO4

at Anode:FePO4+Li(+) +e(-) ------->LiFePO4

at Cathode:LiC6 ------->C6 +Li(+) + e(-)

The Full Reaction (Left :charged, Right :Discharged) being:

Lic6+FePO4< ------->C6+LiFePO4

Nominal Voltage :3.2V

Full Voltage :3.65V

Cycle Life : 1500-2000 Cycles

Specific energy(capacity):90-125 wh/kg

Applications:Power tools ,EVs,Medical,Hobbyist.

NCA(lithium nickel cobalt aluminium oxides):

Anode:Graphite(C6)

Cathode:LiNiCoAlO2

at Anode:NiCoAlO2+Li(+) +e(-) ------->LiNiCoAlO2

at Cathode:LiC6 ------->C6 +Li(+) + e(-)

The Full Reaction (Left :charged, Right :Discharged) being:

Lic6+NiCoAlO2< ------->C6+LiNiCoAlO2

Nominal Voltage :3.6V

Specific energy(capacity):150-220 wh/kg

Cycle Life : 1000-2000 Cycles

Applications : EVs ,Grids

Lithium nickel manganese cobalt oxide(NMC):

Anode:Graphite(C6)

Cathode:LiNiMnCo

at Anode:NiMnCo+Li(+) +e(-) ------->LiNiMnCo

at Cathode:LiC6 ------->C6 +Li(+) + e(-)

The Full Reaction (Left :charged, Right :Discharged) being:

Lic6+NiMnCo< ------->C6+LiNiMnCo

Nominal Voltage :3.6V

Specific energy(capacity):155-200 wh/kg

Cycle Life : 500 Cycles

Applications : EVs ,Grids

Applications:Power tools ,EVs,Medical,Hobbyist,Grid.

LTO(Lithium Titanate):

Replace graphite as an anode material in lithium-ion batteries is lithium–titanium oxide (Li4Ti5O12,LTO) of spinel structure.

Anode:Li4Ti5O12

Cathode:LiNiMnCo(x)

at Anode:Ti5O12+4Li(+) +4e(-) ------->Li4Ti5O12

at Cathode:Li4Ti5O12(x)------->x +4Li(+) +4 e(-)

The Full Reaction (Left :charged, Right :Discharged) being:

Lix+Li4Ti5O12< ------->x+Li4Ti5O12

Nominal Voltage :2.4V

Cycle Life : 3000-7000 Cycles

Specific energy(capacity):60-110 wh/kg

Applications: EVs,Grid storage