Go on and file this one away in the folder of "awesome things that could, but won't ever happen." As the brilliant minds around the world figure out how to solve vicious diseases, move motorcars with peanut oil and send engineers to fix a telescope in outer space, we still can't buy a pack of AA cells that last longer than a month or two in our favorite toy. Some call it a limit of physics, some deem it a conspiracy. Whatever the case, we've no doubt whatsoever that a new silicon-containing carbon material -- designed by Dow Corning Toray to double the capacity of existing