Battery very strong lid is not valuable and much too smooth

Good Morning,
This Battery (white battery cover) is definitely worth the money. He stops at my average use of:
CA 15-20 phone calls daily from approximately ~ 5-10 minutes,
daily e-pup and read pdf ~ 1h with slightly insulated screen
at least 2hrs Wi-Fi
Music or Höhrbuch evening ca ~ 1h
and the usual calendaring and scheduling use no less than for 3 days.
GPS is usually switched off at me!

I'm really excited about the battery!
The battery gets 5 stars but the dish ... which is inferior and too smooth, unfortunately.

That such a powerful battery space needs should be clear. And that thereby also the phone a lot is difficult is not surprising. However, the battery cover is so slippery that my phone is now 3 times geglitscht out of hand now and the battery cover is now broken. He broke in the place where you can open it, the top of the start button on the S4.
Another use is no longer possible, because you get stuck on the breakline and the shell therefore very quickly dissolves the phone.

If this situation could be created by a 'grip, wertigeren battery cover (possibly with a grippy texture on the back - best rubberized), then I would buy immediately, but the same with a second replacement lid.

As mentioned above, the battery is in itself but really very strong and like very much.