eli5 Why can some batteries be recharged and others can’t?

Question

eli5 Why can some batteries be recharged and others can’t?

In: Chemistry

Answer 1

Mainly chemistry and safety.
Some batteries are designed so that the chemistry can work in reverse. After the battery is used and discharged, we can apply a controlled voltage to make some of the chemical reactions work in the opposite direction.
Some batteries are not made that way. When the battery is discharged, the chemical changes that happen are permanent. We can’t undo those reactions – or we can’t undo them safely.