Revive your cellphone’s lithium-ion battery even if you forget the charger. The Xenium is the first phone that you can juice by popping in an AAA battery. It adjusts the current to charge the phone’s main battery for up to three hours of extra talk time. Philips Xenium 9@9j Price not set; philips.com
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.