Preparation and expansion properties of a graphite intercalation compound containing phosphorus

A graphite intercalation compound (GIC) was prepared by the chemical oxidation method using natural graphite flakes, HClO₄, H₃PO₄ and CrO₃ as raw materials with mass ratios of 1:1:2:0.3. It was characterized by SEM, EDS, XPS, FT-IR, XRD and TGA. The expansion volume of the GIC was 350 mL·g^-1 at 300℃ and reached the highest value of 610 mL·g^-1 at 800℃. The expansion volume of this GIC was obviously higher than the GICs using H₂SO₄ as an intercalating agent. The intercalating agents of the GIC were PO₄^3-, ClO₄^- and Cr₂O₇^2-.