Scientists at Waseda University in Japan have come up with a nifty battery. It's made from polymers, it's only 200 nanometers thick, and it's flexible.
This has real and immediate benefits for handheld devices, of course. But the sticking point for all alternative energy sources is always storage. Battery technology is way behind all the other disciplines involved in making and storing energy. It's a very simple equation. Make something as cheap and portable as a gallon of gasoline, with all the energy it has in it. Energy is all around us but we can't store it and transfer it properly. Advances in battery technology are the most important technological advance we can make as a planet. This is a substantial one.