Lithium battery offer greatly increased energy density in comparison with other rechargeable batteries such as lead acid batteries, Ni-MH batteries, etc. The lithium batteries are of following types:
- Lithium polymer batteries
- Lithium-ion batteries
1. Lithium polymer battery
Negative electrode = lithium metal
Positive electrode = transition metal intercalation oxide
During Discharging
In the resulting chemical reaction, the lithium combines with the metal oxide to form a lithium metal oxide and release energy.
During Charging
When the battery is recharged, the chemical reaction is reversed. The lithium is thus both a reactant and the mobile ion that moves through the electrolyte.
The overall chemical reaction is:
xLi + MyOz ↔ LixMyOz
2. Lithium-ion Battery
Negative electrode = lithiated carbon
Positive electrode = lithiated transition metal intercalation oxide
Electrolyte = liquid organic solution or a solid polymer
During Discharging
Electrical energy is obtained from the combination of the lithium carbon and the lithium metal oxide to form carbon and lithium metal oxide.
During Charging
When the battery is recharged, the chemical reaction is reversed.
The overall chemical reaction is:
C6Lix + MyOz ↔ 6C + LixMyOz
Note: An accurate control of voltage is needed when charging lithium-ion battery cells.
Lithium material is ideal as
- It has low density, lithium is light
- High reduction potential
- largest energy density for weight
Properties of Lithium-ion battery
- Lithium-based cells are most compact ways of storing electrical energy.
- Lower in energy density than lithium metal, lithium ion is safe.
- Energy density is twice of the standard nickel-cadmium.
- No memory and no scheduled cycling are required to prolong battery life.
Advantages of Lithium-ion battery
- It has high specific energy(number of hours of operation for a given weight).
- Huge success for mobile applications such as phones and notebook computers.
Disadvantages of Lithium-ion battery
- Cost differential
- Cell temperature is monitored to prevent temperature extremes.
- No established system for recycling lithium-ion batteries.
