Why use Lithium Ion Batteries for Mobile Phones?

Pros:
1. Completely discharged batteries can be safely disposed off in land fills (Environmentally Friendly).
2. Used when High energy density is needed & cost is secondary.
3. Cell Voltage 3.6 V
4. High Capacity
5. Light weight
6. Long shelf life (won't discharge easily)
7. Memory effect resistant.
8. Life span is 12-18 Months.
9. Charging time is 3-4 Hrs.
Cons:
1. Requires protector circuit for over charge (when charged, voltage still rises).
2. Expensive.