If nanotechnology scientists led by the Queensland University of Technology (QUT) are on the right track, it may one day be a reality as cars are powered not by batteries, but their body panels – inside which are sandwiched a new breed of supercapacitors.
Electric cars have a lot of advantages. They don't directly use fossil fuels, they have zero emissions, and the high-end ones perform like a supercar, with an acceleration that leaves your back teeth at the starting line. The drawback is that they depend on very heavy batteries. At the low end, there are lead-acid types that weigh a staggering amount, while the high end vehicles use lithium-ion batteries that aren't much lighter. In theory, lightweight supercapacitors should do a better job with their ability to hold much higher charges, but in practice, aren't quite there yet.
It's a matter of energy density. Lithium-ion batteries have a lot of energy, but are limited in how fast they can discharge it. Supercapacitors can release energy in large bursts, but don't store as much as a Li-ion battery. The trick is to combine the two in the short term, while figuring out how to store more in the supercapacitor in the long term.