I know where to buy that kind of case. You should buy the solar case, it is the case i'm using right now. Solar case is a phone case that has a power bank attached at the back. It also consist of a solar panel that can absorb energy from the sun and convert it to electric energy to be used in charging the power bank.
Wow that is exactly what I need now! Where can we find that?
I also want to own that kind of case! Can you come with us and lead us to the store where you bought it? Please?