Question

what is the reason that some batteries are chargeble whereas others are not?

Answer 1

A rechargeable battery is a secondary battery and a type of electrical battery with one or more electrochemical cells. In this battery electrochemical reactions are electrically reversed. so, it can be used again after charging. Some of the different combinations are nickel-cadmium, lead-acid, lithium ion and more.

A primary cell is not rechargeable. The electrochemical reactions occurring in it cannot be reversed and hence it cannot be used again.