You Do Need power plug adapter while traveling from Sierra Leone to Abu Dhabi.

Here is Why You Need An Adapter

The outlet and plug type used in Abu Dhabi is G and in Sierra Leone are D and G. This is how they look like.

Sierra Leone

In Sierra Leone, outlets of type D and G are in use.

Type D

Type G

Abu Dhabi

In Abu Dhabi, outlets of type G are in use.

Type G