Li-Polymer (Lithium Polymer) is still quite rare and an even more advanced type of batteries. That technology helps make even thinner and lighter batteries. Lithium Polymer batteries are molded into more varied shapes and it will be squeezed into smaller phone casings. Lithium Polymer Battery (Li-Poly) is the newest and most advanced technology for cellular phone batteries. This brand new chemistry of battery allows for the most compact cells available. Li-Poly batteries are extremely light and thin and allow the most battery life for the size. Lithium Polymer cellular batteries share all of the benefits of Li-ION batteries but will last over twice as long.

The Li-polymer differs from other battery systems in the type of electrolyte used. This electrolyte resembles a plastic-like film that does not conduct electricity but allows the exchange of ions (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.

The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile. There is no danger of flammability because no liquid or gelled electrolyte is used. With a cell thickness measuring as little as one millimeter (0.039 inches), design engineers are left to their own imagination in terms of form, shape and size. Theoretically, it is possible to create designs which form part of a protective housing, are in the shape of a mat that can be rolled up, or are even embedded into a carrying case or a piece of clothing. Such innovative batteries are still a few years away, especially for the commercial market. This lithium polymer innovation will go long way in reducing the weight of the cell phone. The major reason for switching to Li-ion polymer is form factor.

The main advantages are:
- It provides more than three times of energy density
- Polymer electrolyte allows for flexible design
- The design of the battery is as one millimeter (0.039?) in thickness
- It looks very slim unlike other prevailing batteries
- The batteries are molded in a more variety of shapes and sizes.