Question about Samsung Special battery 18650 Flat-Top

You don't need a special one, you need a suitable charger.

A 18650 battery has a diameter of 18mm and a length of 65mm. Measure an AA battery/rechargeable battery. You will find that AA is a lot smaller. So the size of the battery does not fit.
AA batteries are usually NiMH (nickel-metal hydride), rarely NiCd (nickel-cadmium). The 18650 battery here is a Li-Ion (lithium-ion) battery. The charger must also be suitable for the type of battery used (NiMH, NiCd, Li-Ion, etc) or support the corresponding battery technology.

There are chargers that can charge different battery sizes AAA/AA/18650/etc and different battery technologies (NiMH, NiCd, Li-Ion, etc). These are not special in my eyes, they can simply do a bit more than "normal" ones. They don't necessarily have to be expensive for what they can do.