Courtesy Alex WalkerResearchers from Rice University have rethought the battery. Typically, batteries are made up of 5 layers: a positive and negative electrode, each with a metal current collector, and a polymer separator. These layers are manufactured in sheets and then rolled into cylinders. Rice researchers realized that each of these layers were available, or could be created, in sprayable form. They used lithium titanium oxide and lithium cobalt oxide for the anode and cathode, existing metallic paints and carbon nanotube mixtures for the current collectors, and a chemical hodge-podge with a very lengthy name for the separator layer. The result is an ultra thin (a fraction of a millimeter thick) lithium ion battery.
In their first experiment, researchers sprayed each consecutive layer onto nine bathroom tiles, topped with a solar cell. The resulting batteries were able to power 40 LEDs for six hours.
In its current state, this method is too toxic to be used outside a controlled environment, but with a little tweaking, a safe alternative will be found. At that point, any surface could be a battery!