Influence of heat treatment of CrO₃-graphite intercalation compounds on subsequent electrochemical intercalation of sulphuric acid

Abstract

A sudden cathodic jump appearing on the potentiodynamic curves during subsequent electrochemical intercalation of 18 M sulphuric acid into chromium trioxide-graphite intercalation compounds (CrO₃-GICs) is preserved for CrO₃-GICs heated at a temperature lower than that of the decomposition of the intercalate, but vanishes completely after CrO₃-GICs are thermally transformed into the physical mixture of graphite and lower chromium oxides. The results have shown that CrO₃-GICs can be prepared, not only by the solvent method but also by the impregnation-dry method. Using a potentiodynamic technique involving the thermal modification of CrO₃-GICs it has been possible to demonstrate the presence of an intercalation phase for CrO₃-GICs which have unclear X-ray diffraction patterns.