Life with a smartphone means a never-ending search for more power. Recharging our phones is a constant concern, especially for people who travel or work away from an outlet. We cross our fingers we will make it to the end of the day, or at least till our next charging opportunity. Also, the older the phone or battery, the more frequently it needs a top off. Now, researchers have developed a cell phone that recharges itself by harvesting ambient radio signals and light — no battery needed. In other words, this phone will never run out of power.