Smart phones have a lot to offer that older model cell phones might not - apps that are fun or practical, internet at your fingertips, and more. However, older models can often boast better battery life because less power is needed to simply text and make phone calls. In fact, too-short battery life is one of the main problems reported by smart phone users. While battery technology has not evolved as quickly as one might like, there are a couple of companies who are trying to find a solution.

Solar Screen Batteries:

French startup SunPower Group is developing an attachable smart-phone screen that can extend the life of smartphone batteries up to 20% by harnessing solar power. The screen includes a layer of solar cells underneath a layer of specially designed lenses. The overlay is now about 82% transparent, and the company is aiming for 90% transparency in the future.

This design is considered an improvement over older versions of the solar phone, namely Samsung's Crest Solar model which was released in India in 2009. An hour of sunlight would allow this model 5-10 minutes of talk time. The phone's Achille's heel may have been that the solar cells were on the back of the phone - forcing users to keep their phone face-down (and preventing them from looking at their screen), for hours at a time. With the solar cells positioned over the screen, the user won't encounter this problem.

This new technology should also be relatively inexpensive for consumers.