I loved this idea ever since I saw the picture. It seems that a group of Chinese folks designed the ‘Continuance’ project. As you can see, these are not normal batteries. They feature a USB port that allows you to charge your iPhone.
The Continuance batteries are rechargeable, and they can charge any USB-powered devices (as you see in the picture). I know that this is just a concept design, but considering iPhone’s battery draining time, I am really waiting for an actual product like this.