UPON THE ANODIZATION OF METAL HALIDE GRAPHITE-INTERCALATION COMPOUNDSIN BRONSTED ACIDS

Sulfuric acid, perchloric acid or nitric acid were attempted to interc alate into 2nd stage GICs with BiCl3, NbCl5 or InCl3 as well as into a 4th stage ZnCl2 GIC. In the case of 65% HNO3 it was found that interc alation can only be achieved with the 4th stage ZnCl2 GIC resulting in a biintercalation compound with two empty galleries per elementary ce ll remaining. In contrast, H2SO4 and HClO4 formed saturated structures with all host lattices used as the starting material. Cyclovoltammetr ic measurements indicated that the insertion of H2SO4 or HClO4 into th e 4th stage ZnCl2 GIC proceeds stepwise. During the cathodic sweep the acids are completely deintercalated, as can be proved by X-ray diffra ction measurements. If the insertion of H2SO4 into ZnCl2 graphite is t erminated before all free galleries are occupied, HClO4 can be additio nally inserted to form a triintercalation compound.