Hydrolysis of perchloric acid and sulfuric acid graphite intercalation compounds

Abstract Bronsted acid graphite intercalation compounds (C n ) + A − (HA) x are unstable in contact with water. There are several fundamentally different decomposition processes which may occur alternately or in parallel: 1. i) (C n ) + A − (HA) x + y H 2 O = (C n ) + A − (HA) x (H 2 O) y 2. ii) ( C n ) + A − ( HA ) x + H 2 O = “ C n OH ” + ( x +1) HA 3. iii) 2 (C n ) + A − (HA) x + 2 H 2 O = 2 C n + O 2 + (2x+2) HA also + CO, CO 2 , “surface oxides” By coulometric titration, the irreversible reaction pathway (iii) can be separated from the at least quasireversible pathways (i) plus (ii). Hydrolysis of perchloric acid GICs -pathway (ii)- can be easily followed via neutron activation analysis of Cl. By combination of coulometric titration and neutron activation analysis it can be demonstrated that • higher stage and also pure 1st stage GICs are mainly decomposed according to (iii), • even minor “overoxidation” of the 1st stage GIC results in hydrolysis according to (ii), i.e., all the oxidation equivalents are still kept in the graphite compound, although it is almost free of anions.