Efficient preparation of carbon papers by pyrolysis of iodine-treated Japanese paper

A novel carbon paper has been prepared by pyrolysis from traditional Japanese paper called washi in Japan, which is mainly composed of cellulose microfibers. The washi was iodine-treated before pyrolysis. The effect of iodine-treatment on pyrolysis of the washi was investigated using thermogravimetric analysis. The structural and electrical properties of the carbon papers were also investigated using Raman scattering, X-ray diffraction, electron microscopy, and resistivity measurements. The iodine-treatment prevents cellulose from thermally decomposing and is effective in increasing the carbon yield and retaining its fibrillar structure. Porous carbon papers consisting of many micro and nanofibrils were prepared by the pyrolysis of the iodine-treated washi at 800 °C. Those prepared at 800 °C and then heat-treated at higher temperatures than 1800 °C show electrical conductivities of 3 S cm−1 and 24–27 S cm−1. The degree of crystallinity and the electrical conductivity of the papers are improved by the heat treatment at higher temperatures.