iPhone battery life is a huge problem that I hear people all around the world bitch about.
Here are my ideas to solve it:
1. Put a solar panel on the back of the phone. This will give you the ability to charge anywhere there is light.
2. Implement kinetic and heat inductors. This will be the phone charges when it moves and when its in your pocket.
3. Have lock screen access to turn off and on the biggest battery drainers. Including 3g/4g/LTE/WiFi.