Bi-intercalation process of high stage metal chloride-graphite intercalation compounds

Stage-4 AlCl3-GIC prepared by the standard two-zone method were oxidized galvanostatically in H2SO4. The X-ray diffraction data indicate the stepwise intercalation of H2SO4 into host graphite and no formation of the GBC is observed, whereas AlCl3 is deintercalated in an early step of the reaction. In the case of the stage-4 MoCl5-GIC, the galvanostatic oxidation caused the stepwise bi-intercalation of H2SO4 into the host GIC as well as the displacement of MoCl5 by H2SO4. Alternatively, AlCl3 vapour was allowed to react with stage-3 FeCl3-GIC. The competition between the displacement reaction of FeCl3 by AlCl3 and the stepwise bi-intercalation of AlCl3 into the stage-3 FeCl3-GIC was observed. The bi-intercalation process of such a high stage GIC is explained with a schematic chemical potential diagram, comparing the bi-intercalation into stage-2 GIC.