Angela Belcher

The reason we aren't all driving electric cars has little to do with a Detroit conspiracy. It's that nobody has invented a lightweight, inexpensive battery that can store enough electricity to make such a vehicle practical.

If anyone can change that, it's Angela Belcher. A materials scientist and bioengineer at M.I.T., Belcher, 49, won a MacArthur Foundation genius grant in 2004, and last fall Scientific American named her research leader of the year for her current project: creating an entirely new kind of battery, not by building it but by growing it. Working with several M.I.T. colleagues, Belcher has engineered a virus, known as M13 bacteriophage, that latches onto and coats itself with bits of inorganic materials, including gold and cobalt oxide. That turns each long, tubular virus into what amounts to a minuscule length of wire. Coax these nanowires to line up, and you have the components of a battery that is far more compact and powerful than anything available.

If her battery works as a commercially viable product, that alone could qualify Belcher as a climate-change hero, but her vision is green in other ways as well. Conventional batteries generate a lot of waste during manufacture, and they're a disposal nightmare. But a viral battery essentially grows itself, using water as a solvent, so there's practically no waste. And since much of its relatively small bulk is organic, the battery is partly biodegradable.

Belcher has been tackling a whole new field of science every five years (so far, she has mastered materials science, biochemistry, molecular biology and electrical engineering). Considering her track record, the next thing she decides to study could well lead to yet another remarkable breakthrough.