Have you guys heard about the MIT Capacitor that will store about half as much energy as a Li-ion battery (pound for pound), but about 80 times the power output? Rechargeable about 300,000 times. Supposedly going to market in 5 years, but it’s being developed with the help of the “Ford/MIT alliance”. It has the potential to be pretty cheap. It uses Carbon Nanotubes to increase the surface area inside the capacitor.