You Do Need power plug adapter while traveling from China to Western Sahara.

Here is Why You Need An Adapter

The outlet and plug type used in Western Sahara are C and E 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

Western Sahara

In Western Sahara, outlets of type C and E are in use.

Type C

Type E