I have a coffee can full of old batteries. I don't want to toss them in the trash – those things leak all sorts of unfriendly stuff into the environment. Each time I look at the can, I think – why can't they come up with an environmentally friendly battery? I know Doc from one of the Back To The Future movies used old banana peels and other odds and ends from the garbage to fuel his car. . . why are we still making batteries that cause tree huggers to shudder? Well – let tree huggers rejoice. Scientists have also found inspiration from the tall timbers.