Electricity is nothing like gas. You can't just pump a tank full of it into your electric car, which means that we're reduced to lengthy charge times or inefficient compromises like battery swap stations. MIT researchers may have come close to solving this problem with a battery goo that you can pump just like gas.
They're calling this black sludge "Cambridge crude," and it's really two different types of goo, each holding charged particles suspended in semi-liquid electrolyte, sort of like how quicksand is comprised of sand particles suspended in water. There's anode goo, and there's cathode goo, and when the two goos are separated by a goo-separating membrane, charge moves from one goo over to the other goo, generating current to power your car.
When all the charge has been used up, you can pull over to a goo station, which will suck out your used goo and pump new goo back in. Or, when you get home, you can plug your car into a wall socket and recharge your goo that way. So it's like having all the advantages of being able to pump gas, with the added advantage of being able to fill up at home, too.
And it gets better. The goo batteries are cheaper to build than conventional lithium-ion batteries, and they're not dependent on any particular goo chemistry, so as we get better at cooking up more efficient and tastier goo, we can just pump that in instead. The MIT team received a DARPA grant to make this all happen, and by 2013, they should have a reduced-scale system operational and serving as a prototype replacement for electric car batteries.