SQL Server 2014 SP2, backup and restore with powershell
You can use dbatools which is powershell based.
For your case you need to have a 2 step approach.

use the cmdlets in Backup and Restore – Certificates


Backup-DbaDbCertificate
Backup-DbaDbMasterKey
Restore-DbaDbCertificate

then use Copy-DbaDatabase with -BackupRestore switch. Alternately, you can use Backup-DbaDatabase and then Restore-DbaDatabase as per your needs.