But all have on thing in common - technically a single unit is known as a cell and multiple units together are known as "Batteries" Thus the "Battery" in a laptop computer may consist of 6 or more ...

French researchers have announced a prototype of an 18650 sodium-ion battery ... but it maps to the cell size (18 mm in diameter and 65 mm long). The batteries usually use lithium-ion technology.

If you do not want to purchase from the links below, please ensure the battery meets the above requirements. Amazon bans the sale of 18650 batteries, but you may still be able to find some there.