Influence of the primary ZnCl 2 intercalate on electrochemical biintercalation of H 2SO 4 into graphite

Abstract

The aim of this paper is to investigate the mechanism of the subsequent intercalation of H 2SO 4 into ZnCl 2-graphite intercalation compound (ZnCl 2-GIC). The X-ray diffraction analysis (XRD) and two electrochemical methods (cyclic voltammetric and galvanostatic measurements) were used to investigate the transformation of the starting ZnCl 2-GIC to the ternary ZnCl 2–H 2SO 4-GIC. Based on XRD patterns it is concluded that ZnCl 2–H 2SO 4-graphite biintercalation compound (ZnCl 2–H 2SO 4-GBC) and stage-1 H 2SO 4-GIC are formed on attaining the potential 0.9 V. If the electrochemical oxidation of ZnCl 2–H 2SO 4-GBC is continued above the mentioned potential, the reaction between the primary and secondary intercalate takes place. The mechanism of the reaction is discussed based on electrochemical and structural data.