Lithium polymer batteries are thin, rectangular, lightweight batteries used in many electronic items such as notebooks, or laptops, computers and cell phones. "LiPo" and "LiPoly" are common short names for lithium polymer batteries. Lithium polymer batteries are considered to be a safer alternative to lithium ion batteries.

Lithium ion batteries have lithium tightly contained within them. They are powerful batteries and if a short occurs inside them, it can lead to flames. Cylindrical in shape, lithium ion batteries look more like a larger version of AA batteries rather than the narrow, flat, lithium polymer batteries. Lithium polymer batteries are not as prone to flammability as lithium ion batteries are.

As with most all batteries, LiPoly batteries will explode if overcharged, but because they contain polymer gel, LiPoly batteries will not burst into flames if crushed like lithium ion batteries are prone to do. The reason for the difference in flammability reactions between the two types of batteries is the way the lithium is suspended in the batteries. In lithium ion batteries, the lithium ions are suspended by organic solvents that are flammable. In lithium polymer batteries, the lithium is contained in a polymer gel that is not easily flammable.

Lithium polymer batteries cost more than lithium ion batteries and are quicker to lose their capacity. Yet, LiPoly batteries are lighter in weight, making them ideal as a notebook, or laptop, computer battery, as well as a battery for cell phones, personal digital assistants (PDAs), camcorders, hearing aids and digital cameras. The reason lithium polymer batteries are so lightweight is that the polymer gel packs fit into the spaces within the battery and eliminate the need for metal casing to enclose the electrodes.

Both lithium ion and LiPoly batteries are available in rechargeable versions. Zinc-based batteries are another alternative to lithium ion batteries as they are long lasting, not easily flammable and are more environmentally friendly than lithium ion batteries. However, lithium is a popular battery choice as lithium gives the biggest amount of electric energy possible in energy per unit weight of all solid elements.