The difference is in the chemistry; a Lithium battery is a disposable power source composed of lithium metal compounds – the keyword, here, being disposable; Lithium batteries cannot be recharged.
Lithium-Ion batteries, on the other hand, are intercalated, meaning the lithium-ion inside the battery moves between two internal electrodes. This movement or reversibility of the lithium-ion accounts for the battery's rechargeability. You can also buy Lithium Ion Batteries and Li-Ion Rechargeable Batteries from online sources.
What are the benefits of Lithium Ion Technology?
Hold a lot of power and are surprisingly light-weight, especially with consideration to other rechargeable batteries.
Combine single-cell technology with a greater energy reservoir than Nickel Metal Hydride and Nickel Cadmium batteries. They store more power for their size than both NiCad and NiMH.
Hold their charge for significantly longer than other comparable batteries, and provide steady power until that charge is completely gone. Other batteries gradually and consistently lose power as you work. Li-Ion batteries stay strong until the last push.
Are there disadvantages to using Lithium-Ion Batteries?
The disadvantages of using Li-Ion technology are generally few and far between, and technological advancements are making them even less so. Manufacturers have recently improved the Lithium-Ion recipe to reveal a more reliable battery. Still, every giant has its weaknesses:
Li-Ion batteries are sensitive to intense hot and cold temperatures. In extreme temperature conditions, the battery will degrade more quickly.
Li-Ion batteries degrade regardless of frequency of use.
Although these defects are more applicable to the older Lithium-Ion batteries, the possibility of seeing these problems is still worth noting. Fortunately, these said defects are fairly rare and easily avoided.