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

Here is Why You Need An Adapter

The outlet and plug type used in Sierra Leone are D and G and in China are A, C and I. This is how they look like.

China

In China, outlets of type A, C and I are in use.

Type A

Type C

Type I

Sierra Leone

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

Type D

Type G