TR: We’ve heard about all-electric cars for some time, but so far they haven’t panned out – you can’t get very far on a single charge, for example. What has happened in battery development that makes you think this will change?
DS: There was a lot of trial and error with good rules of thumb. But there’s far too many possibilities, and that’s where [MIT materials science professor] Gerbrand Ceder came in, who was using the principles of quantum mechanics to predict the principles of compounds yet unsynthesized. With Gerbrand’s computational materials science, we were able to identify compounds previously ignored in this application.
TR: How good can batteries get?
DS: I think we could easily double [the energy capacity of] what we have right now. We have cells in the lab that, if you run the numbers for a thin-film cell of reasonable size, you end up with two to three times current lithium ion [batteries].
But there’s more. The fantasy of all fantasies is chromium. If we could stabilize chromium [as a material for battery cathodes] and I could…give you a battery with 600–700 watts per kilogram [of energy capacity] with reasonable drain rate, that says good-bye hydrogen economy.
TR: You’ve driven an electric car before. What was that like?
DS: I opened the sun roof, rolled down the windows, and I pulled out. It was like a magic carpet. You hear people laughing, talking, and you’re interacting with the city. I returned the vehicle to the fellow at Boston Edison, and I came back here and said, “I’ve got to work harder. I’ve got to make this thing happen.” The only reason that car isn’t everywhere: it couldn’t go more than 70 miles on a charge. But you make it 270, game over. Anybody who drives it will never go back to internal combustion.
TR: What’s next?
DS: What we need to understand better is systems. Up to now we’ve been asking, “What makes the best polymer electrolyte?” and then we test it against some cathode and some anode. We need to understand what happens when we put the battery together.
Let’s keep the research going. Let’s use the phrase that they used in the early days of nuclear power – “I want this stuff too cheap to meter.” I want these batteries so cheap you can give them away. We’ve got a long way to go, but we’ve got to work at it.