Distribution of intercalates in CrO 3H 2SO 4-graphite and CrO 3HClO 4-graphite bi-intercalation compounds

Abstract

Binary graphite intercalation compounds with sulfuric acid (H 2SO 4GICs), perchloric acid (HClO 4GICs) as well as chromium trioxide (CrO 3GICs) are known to be readily de-intercalated due to cathodic reduction and/or washing with aqueous solutions. The subsequent electrochemical intercalation of sulfuric and perchloric acid into the host CrO 3GICs has resulted in the ternary CrO 3H 2SO 4GICs and CrO 3HClO 4GICs, respectively. The products of the subsequent intercalation composed of the bi- and co-intercalation domains appeared to be very resistant to de-intercalation. The comparison of the results of the X-ray microprobe and X-ray diffraction analysis obtained for the original CrO 3GICs and the cathodically reduced ternary compounds have allowed insight into the structural and chemical changes developing during the subsequent intercalation/de-intercalation process. The knowledge of these properties is helpful for both the better understanding of the intercalation mechanism of the acids into the host CrO 3GIC and the elucidation of the extremely high stability of the ternary compounds.