You Do Need power plug adapter while traveling from Liechtenstein to Brazil.

Here is Why You Need An Adapter

The outlet and plug type used in Brazil are C and N and in Liechtenstein are C and J. This is how they look like.

Liechtenstein

In Liechtenstein, outlets of type C and J are in use.

Type C

Type J

Brazil

In Brazil, outlets of type C and N are in use.

Type C

Type N