Electrochemical intercalation of HClO4 into graphite and CrO3-graphite intercalation compound

Electrochemical intercalation of HClO4 into both the graphite flakes and stage-3 graphite intercalation compound with CrO3 (CrO3GIC) is discussed on the basis of the slow potentiodynamic scanning and X-ray diffraction analysis. It has been shown that intercalation of HClO4 is much faster into CrO3GIC than into the pristine graphite. The differences in the intercalation/deintercalation processes depending on the kind of host matrix indicated that the ternary stage-1 CrO3HClO4GIC (TGIC) is formed due to the insertion of the HClO4 intercalate into the host CrO3GIC. In contrast to the binary HClO4GIC, the cathodic deintercalation of stage-1 CrO3HClO4TGIC and stage-1 TGIC-graphite oxide systems leads to the restoration of the starting stage-3 structure instead of pure graphite. As compared to HClO4GIC, the cyclic overoxidation of stage-1 CrO3HClO4TGIC, resulting in the formation of graphite oxide, needs much less positive potentials to occur. The results of this work give credence to the assumption that bi- and cointercalation phases coexist in the product of the subsequent intercalation of HClO4 into CrO3GIC.