@LucD Thanks so much for the quick response. Actually i had tried with both options but no luck still the same issue.
Method invocation failed because [VMware.VimAutomation.ViCore.Impl.V1.EsxCli.EsxCliElementImpl] does not contain a method named 'list'.
At line:22 char:1
+ $fcfirmware = $esxcli.storage.san.fc.list()
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (list:String) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
Object of type 'InternalVimApi_50.ManagedObjectReference' cannot be converted to type 'System.String'.