Electrochemical Intercalation of Sodium Ions into Thermally Reduced Graphite Oxide

The structure of carbon obtained from the thermal reduction of graphite oxide at 900 degrees C after electrochemical storage sodium ions was investigated. X-ray diffraction measurement of the carbon sample after charged to various potentials indicated that sodium ions are stored between the layers of carbon below 0.3V vs. Na/Na+ though the interlayer spacing of it was similar to that of graphite. The lower LUMO energy as revealed from the broad pi* peak in the region of CK observed in soft X-ray absorption measurement was responsible for the intercalation of a large amount of sodium ions into the present carbon material. (C) The Electrochemical Society of Japan, All rights reserved.