One of the most pressing problems smartphone users have these days is the battery life. We've seen a lot of addons, tricks, and gimmicks that aim to extend our smartphone's active use. Manufacturers are also trying to either cram bigger and bigger batteries or include battery saving modes in their devices. Kyocera is attacking the problem from a slightly different angle. At MWC next week, it will reveal a prototype smartphone that, besides being rugged, also include solar charging capabilities at almost no extra cost.