App that closes apps to save battery?

I used to use a android phone and there was a good app that closes previous apps that were opened and deletes them. I know you can double tap on the iphone but i think it would be easier if there was a app that did that and also that deletes everything recently opened

There are no apps available that do what you want. However "battery boost magic" is a new app that boost the life of your battery considerably. It actually works!