Rechargeable batteries are produced in many different shapes and sizes, ranging from button cells to megawatt systems. Typically they initially cost more than disposable batteries, but have a much lower total cost of ownership and environmental impact, as they can be recharged inexpensively many times before they need replacing. Some rechargeable battery types are available in the same sizes and voltages as disposable types. There are three main types of Lithium rechargeable batteries, Li-Ion, Li-Po and LiFePO4.
Lithium-ion (Li-Ion): are common in home electronics. They are one of the most popular types of rechargeable batteries for portable electronics, with a high energy density, tiny memory effect and low self-discharge. They are also growing in popularity for military, battery electric vehicle and aerospace applications. For example, lithium-ion batteries are becoming a common replacement for the lead–acid batteries that have been used historically for golf carts and utility vehicles. Lithium-ion batteries can pose unique safety hazards since they contain a flammable electrolyte and may be kept pressurized.
Lithium-ion polymer (Li-Po): Batteries referred to as Lithium-Polymer are electrically identical to Lithium Ion cells but use a high conductivity semisolid (gel) polymer electrolyte. This allows Li-Po batteries to be manufactured in thinner packages than traditional Lithium Ion cells which use rigid cases (cylindrical or rectangular). This makes them a highly favourable compact battery for use in tablet computers and many cellular telephone handsets.
Lithium iron phosphate (LiFePO4): is a technology proving to overcome the safety concerns that exist with Lithium ION (Li-ION) and other lithium battery technologies because it is chemically more stable. In particular, LiFePO4 is able to deliver extremely high surge currents without risk of the battery chemistry breaking down (and the battery exploding), holds a charge for a very long time, and is far more stable when exposed to high heat and other environmental conditions. LiFePO4 is finding a number of roles in vehicle use and backup power.
http://en.wikipedia.org/wiki/Rechargeable_battery
http://en.wikipedia.org/wiki/Lithium-ion_battery
http://en.wikipedia.org/wiki/Lithium_polymer_battery
http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery