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

Here is Why You Need An Adapter

The outlet and plug type used in China are A, C and I and in Mayotte are C and E. This is how they look like.

Mayotte

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

Type C

Type E

China

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

Type A

Type C

Type I