Sony's been working on "bio batteries" for a while now. It kicked off using the glucose from sugary drinks or juice, but now the Japanese electronics giant is taking a more eco-friendly route with its recycled paper battery.
It's extremely similar, at least in principle, to the pop-drinking battery; it's just got an extra step -- digesting the cellulose in paper into glucose. Here comes the science!
Cellulose, the main constituent of paper and card (anything derived from wood), is actually made up of long chains of glucose molecules. In essence, Sony's using an enzyme called cellulase, which cuts the links in the cellulose chains to release glucose molecules. From there, another set of enzymes digest the glucose producing hydrogen ions and electrons. The electrons are routed around a circuit, therefore generating an electric current. The electricity can then be used like the juice from any other battery, in this case powering a puny fan -- baby steps. The second stage, digesting the glucose, is the same; but using paper waste is a load more environmentally friendly.
I can't see this actually being useful any time soon; but it'd be awesome if you could just shove your waste paper in your electric car to power it up -- I'd finally have a use for that Metro they force on me every morning. [Sony via Physorg via Engadget]