Ordinary copy paper can be made highly conductive by treating it with a simple water-based dispersion of carbon nanotubes. Bing Hu and other graduate students under Stanford researcher Yi Cui published a paper in Proceedings of the National Academy of Sciences of the United States of America (PNAS) describing the use of such conductive paper to create high-performing prototype supercapacitors, batteries, and fuel cells. He also studied the wear resistance of the nanotube ink and found that it bonds very tightly to the paper; his data show that soaking, rinsing, and wringing-out in water does not significantly affect the properties of the treated paper. The supplementary information for his PNAS paper is freely available for download and describes his experimental methods in detail, including the recipe for his ink and the trick of reloading a commercial highlighter with it. [via Science Daily]