Powershell Copy and Rename Folder

Question

I'm trying to copy one folder with every subfolder and files to another directory. Now what I want to do is rename the copied folder after a specific scheme.

For example the folder is for the category "Train", I want to add "B_" to the name.

What I have for now is following:

$PathFolder = $FileBrowser.SelectedPath
# $PathFolder2 = "B_" + $FileBrowser.SelectedPath

$PathDestination = "C:\Users\*\Desktop\"

$charCount = ($PathFolder.ToCharArray() | Where-Object {$_ -eq '\'} | Measure-Object).Count

$FolderName = $PathFolder.split('\')[$charCount]

if ($CB_Bahnlinien.Checked) {
    $x = Copy-Item -Path $PathFolder -Destination $PathDestination -Recurse -Force -PassThru | Rename-Item -NewName "B_$FolderName" -Verbose
    # $x = Rename-Item -Path "$PathFolder" -NewName "B_$FolderName" -PassThru | Copy-Item -Path $PathFolder2 -Destination $PathDestination -Recurse 
    if($x) {
        $error_msg = $error[0].exception.message
        [System.Windows.Forms.MessageBox]::Show($error_msg,"Achtung!",0)
    } else {
        [System.Windows.Forms.MessageBox]::Show("Erfolgreich kopiert " + $FolderName,"",0)
    }
}

The Problem is that it copies the folder with the content and besides that it creates a new folder with the name as it should be but without the content. Also it doesn't even copy everything from the folder?!